Re: Sony tells DSLR shooters they're idiots

Discussion in 'Digital Photography' started by Trevor, Dec 5, 2012.

  1. Eric Stevens <> wrote:
    > On Thu, 20 Dec 2012 16:44:10 +0100, Wolfgang Weisselberg
    >>Eric Stevens <> wrote:
    >>> On Wed, 19 Dec 2012 01:04:23 +0100, Wolfgang Weisselberg
    >>>>Chris Malcolm <> wrote:
    >>>>> In rec.photo.digital.slr-systems Wolfgang Weisselberg <> wrote:


    >>>>>> Underexposing for less clipping is a feature many DSLRs now
    >>>>>> do regularly. Called "Active Lighing" or somesuch. Works ---
    >>>>>> you guessed it --- with JPEG.


    >>>>> If you're referring to the kind of things Nikon calls "active D
    >>>>> lighting", Sony "dynamic range optimisation", etc. these usually
    >>>>> involve a slight underexposure,


    >>>>Oh, I wouldn't call 1 stop slight.


    >>>>> but that's incidental.


    >>>>Nope. Changing the exposure is neccessary to keep more of
    >>>>the brightest parts from clipping IN THE RAW SENSOR DATA.
    >>>>Can't unclip in JPEG what is clipped in RAW.


    >>>>> They're tone
    >>>>> mapping systems to bring out shadow detail while preserving highlight
    >>>>> detail.


    >>>>Which --- see above --- *requires* underexposure.


    >>> Not when I only decide to use Nikon's so-called 'D-Lighting' in
    >>> post-processing in the computer.


    >>In which case you've to underexpose manually or get clipped
    >>highlights in the RAW. Unless of course your scene doesn't have
    >>much dynamic range and you don't need D-Lighting in first place.


    > Yes, that sometimes happens, in which case I delete the D-Lighting. On
    > other occasions it makes a noticable difference to the image. It's
    > very useful when it comes to helping sort out difficult exposure
    > situations.


    Any reason why you wouldn't decide how much highlights to blow
    and expose accordingly, pushing shadows in post (and
    adjusting the curves) as needed?

    -Wolfgang
     
    Wolfgang Weisselberg, Dec 24, 2012
    #41
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  2. In rec.photo.digital Wolfgang Weisselberg <> wrote:
    > Chris Malcolm <> wrote:
    >> In rec.photo.digital Wolfgang Weisselberg <> wrote:
    >>> Chris Malcolm <> wrote:
    >>>> In rec.photo.digital.slr-systems Wolfgang Weisselberg <> wrote:


    [snip]

    >> They [previews] usually show you what you'll get. In certain
    >> circumstances they don't. You're right that learning what those
    >> circumsntaces are, and if an inquisitive person, why, is a good and
    >> useful idea. A brief glimpse of the taken shot flashed up on the
    >> LCD or EVF will immediately show you the difference between preview
    >> prediction and result.


    > So you need the same time to assess the correctness of the
    > preview mode as you need to check any other parameters.


    Not necessarily. For example if the EVF (or LCD panel) is set to show
    the resulting image after the shot there is an instant flick between
    pre and post views which highlights small differences rapidly &
    effectively. Astronomers use that same process to draw the eye to very
    small changes which are otherwise imperceptible.

    > Unfortunately, aperture and exposure time is well behaved,
    > but preview prediction is much less so. Thus you need to
    > check the results mor often and for a much longer time.


    I don't find that to be the case.

    [snip]

    >> [...] It would be nice if our cameras' auto functions were all
    >> infallibly perfect, but none of them are, and it's part of any
    >> inquisitive and careful photographer's work to find out when they
    >> can't be trusted.


    > Incorrect. There can be an inquisitive and careful photographer
    > who stays with full manual for his work.


    True, but the more restricted is the range of inquisitive
    investigation the less it deserves the title.

    [snip]

    >>> People are doing video with their cameras?


    >> No in the sense that both photographer and camera are in taking still
    >> photographs mode. Yes in the sense that some of what the camera has to
    >> do to offer this kind of preview mode is similar to some aspects of
    >> video.


    > Sure, the camera needs to read the sensor and display the
    > image in real-time --- but an optical view finder does the same.


    Not the same. An optical viewfinder shows the image the lens is
    presenting to the image sensor. An EVF shows you what the sensor makes
    of it. An EVF in preview mode shows you in addition what your selected
    jpeg processing options etc. have on the image.

    [snip]

    >> The preview mode can equally well be used as an aid to
    >> intelligent experiment by the curious.


    > True.
    > Psychoactive drugs can equally well be used as an aid to
    > therapy, too.


    > Unfortunately in the case of drugs, this turns out to be
    > unlikely in most cases of drug use. I fear it'll be the same
    > with preview mode: only a very few will use it "as an aid to
    > intelligent experiment".


    You may be right. But I don't choose my photographic equipment or
    develop my techniques with a view to their use in educating the
    unwilling or incurious. Nor do I or my doctor choose my drugs on the
    basis of how addicts abuse them.

    [With resepct to finding te right shutter speed to blur moving skaters
    while keeping stationary skaters sharp]

    >> It takes a little skill to judge it in preview mode, true. I found it
    >> quicker use it to home in to the right kind of shutter speed and then
    >> use chimping for the final refinement (if there was time) than use
    >> chimping all the way. That's arguably because I'm not a sports shooter
    >> and shoot this kind of ice rink shot about once every two years.


    > I'm curious. My first guess would be 1/500 or 1/1000 on a
    > moderate tele to freeze action. What was your first guess
    > after preview mode and your final shutter speed=


    The point was not to freeze action but to blur it! The shutter speeds
    needed were generally in the 1/10th to 1/100th sec range. Preview mode
    usually let me get it right, and when it didn't it wasn't more than a
    stop out.

    >> It's
    >> also possible that all kinds of variable eye and brain physiology
    >> comes into this and that some people will find the preview facilities
    >> far more annoying than useful.


    > I would find it plainly impossible to see the difference between
    > tack sharp and mostly sharp in preview.


    Which I expect is why the facility to magnify the preview image up to
    image sensor pixel level was provided.

    > It would only tell
    > me major blur or no blur --- not only because the EVF doesn't
    > have that much resolution,


    The preview magnfication of the sensor image is done by computer not
    lenses, so the resolution of the EVF doesn't put any limits on the
    magnification.

    > but because I can't look that fast.


    A natural limit which applies to any technology which relies on you
    seeing what's happening.

    > Same with DOF, but I can get an idea of DOF by stopping down
    > the lens.


    A nice feature of EVFs is that stopping down the lens doesn't dim the
    view unless you want it to. Very handy when doing long tripod
    exposures in churches or carefully selecting DoF in interior shots lit
    by strobes.

    [snip]

    > I can't really judge sharpness without magnification,
    > much less in a limited-dot/3=pixel-viewfinder.


    You seem to think the magnification is done by optically magnifying
    the view of the EVF screen. It's not. It's done the same way as your
    computer can zoom into pixel level detail on your image editor, even
    if it's a 50MP image and your computer monitor has only 1MP.

    [snip]

    >>> Not with any refresh rate that's needed to
    >>> even sorta track the subject, and not without a 10x (or more)
    >>> loupe, which severely cuts your perception of the scene.


    >> A 10x loupe?? Why on earth would you ever need a loupe on a camera
    >> which can easily magnify any part of the image,


    > That isn't called a loupe?


    No. A loupe is a lens. Do you describe zooming in and panning around
    when inspecting a large image on your computer monitor as "using a
    loupe"? I suggest you look up "loupe" in a dictionary.

    [snip]

    > If you don't want more than sorta-WYSIWYG, preview mode only,
    > then that's perfectly fine with me, use preview mode, stay
    > with preview mode.


    > But you cannot transfer what you learn there to other modes,
    > not without deliberately and consciously working on it.
    > In other modes you can't get away ignoring the numbers and
    > their meanings --- you learn by default.


    But underneath the image are displayed the shutter speed, aperture,
    ISO, plus a lot more which you can choose whether or not to display.
    That facilitates the learning if learning is what you want to do. You
    might be right that it also helps you to avoid learning if that's what
    you want to do.

    It doesn't bother me if the preview mode of my camera might help the
    lazy and ignorant to take photographs without learning what's going
    on. I've managed to avoid having to teach people who didn't want to
    learn all my life and I don't intend to start now.

    [snip]

    >> It's harder to follow action with that than simply
    >> looking at the straight image through the viewfinder, but it's
    >> easier to follow the action with it than with a 10x loupe.


    > Yep, try that sometime. Take a flock of birds flying
    > overhead, track one bird with a long lens and see in the
    > viewfinder if his eye is tack sharp.


    So what? I'm talking about using a specific camera feature and method
    to help solve a particular photographic problem -- selective speed
    blurring of moving skaters.

    You're quite right that it would be silly to use that method for all
    sorts of other photographic problems. I've tried getting sharp
    photographs of birds in flight with a 500mm lens and I use quite
    different methods, including the use of an adapted gunsight in
    combination with an AF which has been specifically calibrated for that
    purpose.

    [snip]

    >>> Can't judge 'tack sharp' without a refresh
    >>> rate faster than 2 times a second without training (the same
    >>> training which would have told you immediately how long you can
    >>> hold at that focal length with that lens).


    >> Apparently not, because I seem to have the first training mentioned
    >> above without having the last mentioned above.


    > Ah, you use static motives and a tripod.


    For the blurring of moving skaters kind of problem I prefer a monopod
    plus image stabilisation.

    >> I do know about the
    >> reciprocal of the focal length for shutter speed, that you have to
    >> adapt that to digital sensor size and resolution, add in the image
    >> stabilising factor when appropriate, adapt it to the holding method
    >> employed (e.g. elbows on wall, monopod, tripod), factor in wind,
    >> factor in unusual rotational inertias (e.g. long reflective vs
    >> refractive lens), etc etc.


    > Yep. So how many bodies and lenses do you regularly use?


    Depepnding on how you define "regularly" anywhere between five and ten
    lenses. I'm not counting lenses I use less than once a year. I usually
    carry at least three. I only use my backup camera when I want to
    reduce lens changes. It doesn't do anything better than my best camera
    so it never goes out alone. That varies between more than once a week
    to less than once a month so I wouldn't call my use of two bodies
    regular.

    >> In other words predicting steady hand holding speed in advance is an
    >> educated guess which often needs verification and adjustment in
    >> practice.


    > Really? I try a new technique, I see what comes out, I
    > adjust as necessary to my goal, I remember what works and
    > what not for next time.


    Sounds like you're blessed with a much better memory than I've ever
    had. I sometimes solve a problem on the run in a busy shoot and by the
    time I get to reviewing the results on the computer I've forgotten how
    I did it. But of course not entirely, because next time I hit the problen
    I'll solve it faster and remember it better.

    >>> Can't follow the
    >>> action at 2 fps --- probably can't even keep the camera steady.


    >> Many action shooters employ the both eyes open method for following
    >> action.


    > Action shooters generally do not employ preview mode, though:
    > they don't want the additional *variable* lag between photons
    > hitting the sensor and dots lighting up on the EVF.


    Of course. In that case you'd either avoid using the laggier kinds of
    EVF processing or avoid preview mode altogether. The fastest and most
    difficult kind of action shooting I do is birds in flight with a 500mm
    lens and for that I don't use the camera's viewfinder at all. I use an
    adapted gunsight which lets me use both eyes on the whole scene.

    [snip]

    >>> Much easier to freeze one frame and evaluate it at leisure,
    >>> once you have a rough idea (which requires about as much
    >>> training as using the preview properly) --- and exactly that
    >>> is what happens when you take a shot.


    >> That is indeed much easier, but sometimes there isn't time to do that.


    > Then there isn't time to play with preview modes either.


    Not my experience. I find I still have time to use preview when
    there's no time to shoot and review. It's better at that than I
    expected before trying it.

    >>> SURE, if you have NO idea at all, then a preview helps ---


    >> I find it also helps in my case where I have quite a good idea, having
    >> learned my photgraphy back in the old days before there was even
    >> autoexposure let alone autofocus.


    > You're saying you're still surprised by aperture or exposure
    > time settings?


    Surprised is too strong a word. But where there are conflicting
    demands and aesthetic trade offs involved I like to experiment with
    different compromises. Anything which shortens the time between
    experiment and result is useful, especially when the shortening steps
    over the important boundary between experiment and check into
    interactive process control.

    >>> provided you have enough ideas how to *use* the preview mode.
    >>> And it's limitations. And where it fails. On your camera.
    >>> In your specific preview mode setting.


    >> Perfectly true. These are all things you have to learn for each new
    >> camera, just as in the old days you had to learn about different films
    >> and developing techniques.


    > But you didn't need to relearn all of exposure time and
    > aperture. Which is what the preview mode supplies. Preview
    > doesn't do newer generations of sensors or digital darkroom.


    It does do newer sensors because it's tied to the sensor. And it does
    do some digital darkroom techniques -- those which have become part of
    the rapid jpeg processing repertoire of the camera such as colour
    balancing and some kinds of tone mapping.

    But if you're referring to learning and experience which is specific
    to certain makes and models of camera you're right. That lack of
    generality is also true of autofocus. That doesn't stop autofocus
    being very useful, nor does it stop it being useful to learn exactly
    how a specific kind of autofocus technology works and where and why it
    fails.

    >>> Which means the
    >>> knowledge doesn't carry over.


    >> Your arguments are much too black and white. That not all the
    >> knowledge carries over doesn't mean that none of it does. All the
    >> knowledge doesn't carry over. But a useful amount of it does.


    > Yet with aperture and exposure time almost all carries over,
    > even switching sensor sizes.


    A surprising amount of what I learned in my film shooting days has
    turned out to have been oversimplified and overgeneralised. That's
    mainly been due to increasing sensor resolution revealing unsuspected
    problems in earlier cruder generalisations. Rather like the way
    improved detail resolution in scientific measuring instruments reveals
    the simplifications and overgeneralisations in earlier mathematical
    models.

    [snip]

    >> In fact angle of view is more independent and useful than
    >> "equivalent focal length" which IMHO is a silly fudge of an incomplete
    >> generalisation.


    > So you'd write an angle of view on a lens --- which is then
    > attached to a 35mm-sized sensor, a 1.6x crop sensor, a 2x crop
    > MFT and maybe even to a 2.7x '1"' sensor. For which sensor
    > would you write the angle of view?


    None, for exactly the same reasons I wouldn't write "equivalent focal
    length" on a lens either.

    >>>> Quite apart from learning, a much faster way of geting the speed blur
    >>>> you want, sufficiently much faster that in five minutes shooting you
    >>>> can come away with many more good shots of a much greater variety than
    >>>> without preview.


    >>> If you need more than 20 seconds to try-chimp the right speed
    >>> blur, you need to use your camera more than 2 times a year.


    >> No, you need to use your camera for that kind shot more than two times
    >> a year. I use my camera more than once a week, but I only try that
    >> specific ice rink problem about once every other year. Two years ago I
    >> spent about fifteen minutes on it, during which time I learnt a
    >> lot. This year I spent only a few minutea on it. I was stopped by a
    >> security guard who was worried that I might have a perverted interest
    >> in photographing child skaters or be planning a terrorist attack.


    > And next year you'll be arrested for carrying a camera.


    I doubt it. In the UK over the last few years photographers and
    lawyers have succeeded in getting the law clarified and better
    guidelines issued from the government to police and security
    personnel. That's led to improved relations between photographers,
    police, and security guards. I used to get harassed often enough that
    I carried a copy of the relevant legislation in my gear bag. I don't
    now because there's much less harassment.

    The ice rink incident above was unexpected and untypical. One of our
    group of photographers emailed the security company a copy of the
    legislation and guideliens for police and security. The reply suggests
    an improved attitude would be forthcoming. Later experiences by other
    photographers suggests it has.

    >>> Which leaves you with 4:40 pure shooting time. Which means
    >>> you need to machine-gun with the preview mode in the first 20
    >>> seconds *and* get all the "many more good shots" there *and*
    >>> all the "much greater variety". Which is as likely as being
    >>> struck by lightning.


    >> No idea what that argument means.


    > Basically: If you need to chimp for a rather long time to
    > find the right settings, you don't know your camera well.


    I don't. It's a recent acquisition. It takes me at least six months to
    get to know a camera well. But on the other hand the exposure
    parameters I'm playing with are in this case largely camera
    independent.

    > If you don't need to chimp for a long time,


    Which I don't.

    > I call your
    > ""sufficiently much faster that in five minutes shooting you
    > can come away with many more good shots of a much greater
    > ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
    > variety than without preview" bull.
    > ^^^^^^^


    Experiment trumps speculation. My experiment, your speculation.

    >> It does you credit that you're worried about the educational state of
    >> lazy or stupid photographers and would rather the market insisted on
    >> supplying them with cameras they couldn't work without a proper
    >> scientific understanding of camera technology.


    > Where did I require that one enter Maxwell's equations into
    > the camera before the shutter works? Or alternatively, the
    > theory of charge transport in semi-conductors? Or maybe how
    > to design and make a processor for the camera?


    When you look up "loupe" in your dictionary look up "eristic argument"
    as well :)

    >> Unfortunately the
    >> market is based on consumer choice.


    > Really? So where are the cameras many ask for?


    In the shops.

    [snip]

    >>> So why not leave off the preview mode (instead of wasting
    >>> months or years on it) and start being in a fix and thus
    >>> learning immediately? Please use short, simple words to
    >>> explain that ...


    >> Because that learning process is less fun, and I'm easily bored. Plus
    >> preview lets me get a lot more fairly good shots while I'm doing the
    >> learning. Helps my motivation. I also suspect that learning which is
    >> more fun works faster and better. But I'm willing to accept that may
    >> be a personal idiosyncracy.


    > I see. You want the easiest way, not the fastest or the
    > best way.


    Not what I said nor meant. I said I wanted the most fun while
    learning. By that I meant playful skill acquisition and problem
    solving. That's always been the best and fastest way to learn for me.
    A friend and cognitive psychologist tells me that's not just a
    personal idiosyncrasy of mine.

    --
    Chris Malcolm
     
    Chris Malcolm, Dec 30, 2012
    #42
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  3. ["Followup-To:" header set to rec.photo.digital.]
    Chris Malcolm <> wrote:
    > In rec.photo.digital Wolfgang Weisselberg <> wrote:
    >> Chris Malcolm <> wrote:


    >>> They [previews] usually show you what you'll get. In certain
    >>> circumstances they don't. You're right that learning what those
    >>> circumsntaces are, and if an inquisitive person, why, is a good and
    >>> useful idea. A brief glimpse of the taken shot flashed up on the
    >>> LCD or EVF will immediately show you the difference between preview
    >>> prediction and result.


    >> So you need the same time to assess the correctness of the
    >> preview mode as you need to check any other parameters.


    > Not necessarily. For example if the EVF (or LCD panel) is set to show
    > the resulting image after the shot there is an instant flick between
    > pre and post views which highlights small differences rapidly &
    > effectively. Astronomers use that same process to draw the eye to very
    > small changes which are otherwise imperceptible.


    Blink comparators switch many times between 2 images, not
    just once --- for a very good reason. And even then you need
    perfect alignment *and* no blanking. Oh, and does your EVF
    or LCD show 10x magnification of the whole image at once?


    >> Unfortunately, aperture and exposure time is well behaved,
    >> but preview prediction is much less so. Thus you need to
    >> check the results mor often and for a much longer time.


    > I don't find that to be the case.


    Interesting.


    >>> [...] It would be nice if our cameras' auto functions were all
    >>> infallibly perfect, but none of them are, and it's part of any
    >>> inquisitive and careful photographer's work to find out when they
    >>> can't be trusted.


    >> Incorrect. There can be an inquisitive and careful photographer
    >> who stays with full manual for his work.


    > True, but the more restricted is the range of inquisitive
    > investigation the less it deserves the title.


    Why should someone who investigates what's effective in
    his photography and doesn't need automatic functions for
    his work investigate something so unimportant to his work?
    Do photographers routinely learn electronics and program
    firmware and study algorithms for deinterlacing and the
    theoretical groundwork for image manipulation, lest they be
    called not inquisitive enough?


    > An optical viewfinder shows the image the lens is
    > presenting to the image sensor. An EVF shows you what the sensor makes
    > of it. An EVF in preview mode shows you in addition what your selected
    > jpeg processing options etc. have on the image.


    An EVF in preview mode *sometimes* show you an image
    *downsampled to 0.3-0.4 MPix* of what the sensor and JPEG engine
    made of the light that arrived through the lens *some time ago*
    on an *uncorrected* monitor that's usually much too bright in
    low light situations.


    >>> The preview mode can equally well be used as an aid to
    >>> intelligent experiment by the curious.


    >> True.
    >> Psychoactive drugs can equally well be used as an aid to
    >> therapy, too.


    >> Unfortunately in the case of drugs, this turns out to be
    >> unlikely in most cases of drug use. I fear it'll be the same
    >> with preview mode: only a very few will use it "as an aid to
    >> intelligent experiment".


    > You may be right. But I don't choose my photographic equipment or
    > develop my techniques with a view to their use in educating the
    > unwilling or incurious. Nor do I or my doctor choose my drugs on the
    > basis of how addicts abuse them.


    OTOH your doctor doesn't try out a dozen different drug
    combinations on you until he hits one that sort of works,
    at least usually. He does chimp, though.

    > [With resepct to finding te right shutter speed to blur moving skaters
    > while keeping stationary skaters sharp]


    >>> It takes a little skill to judge it in preview mode, true. I found it
    >>> quicker use it to home in to the right kind of shutter speed and then
    >>> use chimping for the final refinement (if there was time) than use
    >>> chimping all the way. That's arguably because I'm not a sports shooter
    >>> and shoot this kind of ice rink shot about once every two years.


    >> I'm curious. My first guess would be 1/500 or 1/1000 on a
    >> moderate tele to freeze action. What was your first guess
    >> after preview mode and your final shutter speed=


    > The point was not to freeze action but to blur it! The shutter speeds
    > needed were generally in the 1/10th to 1/100th sec range.


    i.e. just handholdable.

    > Preview mode
    > usually let me get it right, and when it didn't it wasn't more than a
    > stop out.


    Whatever floats your boat ... you still needed to chimp.

    >>> It's
    >>> also possible that all kinds of variable eye and brain physiology
    >>> comes into this and that some people will find the preview facilities
    >>> far more annoying than useful.


    >> I would find it plainly impossible to see the difference between
    >> tack sharp and mostly sharp in preview.


    > Which I expect is why the facility to magnify the preview image up to
    > image sensor pixel level was provided.


    Which again --- with roller skates --- means you need to have
    your subject pass the part of whatever 0.3 MPix you're currently
    seeing at pixel level and judge in 1/60s (or whatever refresh
    rate you EVF uses) if the subject was tack sharp or only mostly
    sharp --- or reliably follow the subject at that magnification
    without camera shake or blur from the camera movement. At, say
    150mm (35mm equivalent) and 15 MPix that would mean steadying an
    effective 1060mm (and that's only ~7x). That's the same as if
    your skaters filled the frame at 21mm for distance and speed and
    you'd followed someone's belly button at 150mm at that range.

    You'd need to *record* the preview image and then zoom in and
    watch at your leisure, taking a second or 3. Which is
    chimping and works even better with the shutter button.


    >> It would only tell
    >> me major blur or no blur --- not only because the EVF doesn't
    >> have that much resolution,


    > The preview magnfication of the sensor image is done by computer not
    > lenses, so the resolution of the EVF doesn't put any limits on the
    > magnification.


    You either get the whole frame and low resolution, or a tiny
    shred of the whole frame, through which even a stationary
    object will jump around unless you're well braced and have
    steady hands or a tripod. (I can do that. Sort of. Sitting.
    Bracing my heavy 70-200mm lens on my legs and fixating the
    camera with my hands. Which won't work at all with an EVF or
    moving subjects I have to track.)

    It's kinda hard to see 'is tack sharp' or not under these
    circumstances.


    >> but because I can't look that fast.


    > A natural limit which applies to any technology which relies on you
    > seeing what's happening.


    Which is easily circumvented by softly squeezing the shutter
    button and chimping.


    >> Same with DOF, but I can get an idea of DOF by stopping down
    >> the lens.


    > A nice feature of EVFs is that stopping down the lens doesn't dim the
    > view unless you want it to. Very handy when doing long tripod
    > exposures in churches or carefully selecting DoF in interior shots lit
    > by strobes.


    Yes, *please* show me how you evaluate the light, the JPEG
    settings and the DoF in a dark interior shot lit by strobes
    .... in preview mode!


    > [snip]


    >> I can't really judge sharpness without magnification,
    >> much less in a limited-dot/3=pixel-viewfinder.


    > You seem to think the magnification is done by optically magnifying
    > the view of the EVF screen. It's not. It's done the same way as your
    > computer can zoom into pixel level detail on your image editor, even
    > if it's a 50MP image and your computer monitor has only 1MP.


    I KNOW. Still, I can't judge the sharpness of a 24 or 36
    MPix image on a 0.33 MPix (1 MDot) monitor. I can usually
    see if such an image is *quite* unsharp on a large 27"
    monitor (when the image occupies >3 MPix (9 Mdot)). I
    *still* need magnification to judge critical sharpness
    there.)

    > [snip]


    >>>> Not with any refresh rate that's needed to
    >>>> even sorta track the subject, and not without a 10x (or more)
    >>>> loupe, which severely cuts your perception of the scene.


    >>> A 10x loupe?? Why on earth would you ever need a loupe on a camera
    >>> which can easily magnify any part of the image,


    >> That isn't called a loupe?


    > No. A loupe is a lens. Do you describe zooming in and panning around
    > when inspecting a large image on your computer monitor as "using a
    > loupe"? I suggest you look up "loupe" in a dictionary.


    http://www.gregorybraun.com/Loupe.html
    http://www.artissoftware.com/screentools/loupe.html
    http://www.markus-bader.de/MB-Ruler/help/loupe.htm

    Maybe your dictionary is out of date?


    >> If you don't want more than sorta-WYSIWYG, preview mode only,
    >> then that's perfectly fine with me, use preview mode, stay
    >> with preview mode.


    >> But you cannot transfer what you learn there to other modes,
    >> not without deliberately and consciously working on it.
    >> In other modes you can't get away ignoring the numbers and
    >> their meanings --- you learn by default.


    > But underneath the image are displayed the shutter speed, aperture,
    > ISO, plus a lot more which you can choose whether or not to display.


    And on web pages there are ad banners on the top and on each
    site. They're habitually ignored.

    On Windows, there are many cases where you need to confirm a
    detrimental action. But as such pop ups are used for
    everything, people are conditioned to ignore the warning that
    they destroy their installation and click OK.

    Just having the numbers doesn't mean that they're being seen.

    > That facilitates the learning if learning is what you want to do. You
    > might be right that it also helps you to avoid learning if that's what
    > you want to do.


    In your skater example, did you look at the numbers, adjusted
    them and then checked the effect, or did you turn the dials
    till the effect was sorta what you wanted and then looked at
    the numbers? (Or did you ignore the numbers completely?)


    > It doesn't bother me if the preview mode of my camera might help the
    > lazy and ignorant to take photographs without learning what's going
    > on. I've managed to avoid having to teach people who didn't want to
    > learn all my life and I don't intend to start now.


    That's not the kind of person to use preview mode, they use
    full auto everything mode, not even scene modes.


    >>> It's harder to follow action with that than simply
    >>> looking at the straight image through the viewfinder, but it's
    >>> easier to follow the action with it than with a 10x loupe.


    >> Yep, try that sometime. Take a flock of birds flying
    >> overhead, track one bird with a long lens and see in the
    >> viewfinder if his eye is tack sharp.


    > So what? I'm talking about using a specific camera feature and method
    > to help solve a particular photographic problem -- selective speed
    > blurring of moving skaters.


    You're right, preview mode is just applicable to moving
    skaters. :) Phew! Now I'm relieved!


    >>> I do know about the
    >>> reciprocal of the focal length for shutter speed, that you have to
    >>> adapt that to digital sensor size and resolution, add in the image
    >>> stabilising factor when appropriate, adapt it to the holding method
    >>> employed (e.g. elbows on wall, monopod, tripod), factor in wind,
    >>> factor in unusual rotational inertias (e.g. long reflective vs
    >>> refractive lens), etc etc.


    >> Yep. So how many bodies and lenses do you regularly use?


    > Depepnding on how you define "regularly" anywhere between five and ten
    > lenses. I'm not counting lenses I use less than once a year. I usually
    > carry at least three. I only use my backup camera when I want to
    > reduce lens changes. It doesn't do anything better than my best camera
    > so it never goes out alone. That varies between more than once a week
    > to less than once a month so I wouldn't call my use of two bodies
    > regular.


    Do your know your regular lenses well?


    >> Really? I try a new technique, I see what comes out, I
    >> adjust as necessary to my goal, I remember what works and
    >> what not for next time.


    > Sounds like you're blessed with a much better memory than I've ever
    > had. I sometimes solve a problem on the run in a busy shoot and by the
    > time I get to reviewing the results on the computer I've forgotten how
    > I did it.


    You don't have EXIF in your files? There's everything in
    there that you can influence by using the preview mode ...
    You're not using chemical sensors, are you? :)


    >>>> Can't follow the
    >>>> action at 2 fps --- probably can't even keep the camera steady.


    >>> Many action shooters employ the both eyes open method for following
    >>> action.


    >> Action shooters generally do not employ preview mode, though:
    >> they don't want the additional *variable* lag between photons
    >> hitting the sensor and dots lighting up on the EVF.


    > Of course. In that case you'd either avoid using the laggier kinds of
    > EVF processing or avoid preview mode altogether. The fastest and most
    > difficult kind of action shooting I do is birds in flight with a 500mm
    > lens and for that I don't use the camera's viewfinder at all. I use an
    > adapted gunsight which lets me use both eyes on the whole scene.


    Yet wouldn't it be perfect if you used preview mode to have
    the body tack sharp but the tips of the wings blurred to
    show the dynamic movement?


    >>>> Much easier to freeze one frame and evaluate it at leisure,
    >>>> once you have a rough idea (which requires about as much
    >>>> training as using the preview properly) --- and exactly that
    >>>> is what happens when you take a shot.


    >>> That is indeed much easier, but sometimes there isn't time to do that.


    >> Then there isn't time to play with preview modes either.


    > Not my experience. I find I still have time to use preview when
    > there's no time to shoot and review. It's better at that than I
    > expected before trying it.


    That would mean lots of experience with preview, but low on
    experience with exposure times and apertures.

    >>>> SURE, if you have NO idea at all, then a preview helps ---


    >>> I find it also helps in my case where I have quite a good idea, having
    >>> learned my photgraphy back in the old days before there was even
    >>> autoexposure let alone autofocus.


    >> You're saying you're still surprised by aperture or exposure
    >> time settings?


    > Surprised is too strong a word. But where there are conflicting
    > demands and aesthetic trade offs involved I like to experiment with
    > different compromises. Anything which shortens the time between
    > experiment and result is useful, especially when the shortening steps
    > over the important boundary between experiment and check into
    > interactive process control.


    The best shortening would be knowing pretty well which
    combination work. It's sorta like phase AF and contrast AF:
    Phase AF knows the direction and (quite exact) the amount
    of travel, contrast AF is an interactive control process ...
    guess which one is still faster.

    >>>> provided you have enough ideas how to *use* the preview mode.
    >>>> And it's limitations. And where it fails. On your camera.
    >>>> In your specific preview mode setting.


    >>> Perfectly true. These are all things you have to learn for each new
    >>> camera, just as in the old days you had to learn about different films
    >>> and developing techniques.


    >> But you didn't need to relearn all of exposure time and
    >> aperture. Which is what the preview mode supplies. Preview
    >> doesn't do newer generations of sensors or digital darkroom.


    [...]
    > But if you're referring to learning and experience which is specific
    > to certain makes and models of camera you're right.


    Exactly.
    You learn --- and then have to throw away most of it when you
    change cameras.

    > That lack of
    > generality is also true of autofocus. That doesn't stop autofocus
    > being very useful, nor does it stop it being useful to learn exactly
    > how a specific kind of autofocus technology works and where and why it
    > fails.


    AF is fully automatic.
    Full auto mode is fully automatic.
    Preview is fully manual. And slower than full auto.


    >>>> Which means the
    >>>> knowledge doesn't carry over.


    >>> Your arguments are much too black and white. That not all the
    >>> knowledge carries over doesn't mean that none of it does. All the
    >>> knowledge doesn't carry over. But a useful amount of it does.


    >> Yet with aperture and exposure time almost all carries over,
    >> even switching sensor sizes.


    > A surprising amount of what I learned in my film shooting days has
    > turned out to have been oversimplified and overgeneralised. That's
    > mainly been due to increasing sensor resolution revealing unsuspected
    > problems in earlier cruder generalisations. Rather like the way
    > improved detail resolution in scientific measuring instruments reveals
    > the simplifications and overgeneralisations in earlier mathematical
    > models.


    Naah. You've increased the enlargement (you print larger or
    look at 100% with higher resolutions), you needed to factor
    that in even back when.

    What has changed is that you are more variable in your ways.
    But luckily all you need is a simple correction factor.

    Just as switching from Deutschmark to Euro.

    >>> In fact angle of view is more independent and useful than
    >>> "equivalent focal length" which IMHO is a silly fudge of an incomplete
    >>> generalisation.


    >> So you'd write an angle of view on a lens --- which is then
    >> attached to a 35mm-sized sensor, a 1.6x crop sensor, a 2x crop
    >> MFT and maybe even to a 2.7x '1"' sensor. For which sensor
    >> would you write the angle of view?


    > None, for exactly the same reasons I wouldn't write "equivalent focal
    > length" on a lens either.


    Thus the focal length is most useful, and from there you get
    trivially to equivalent focal length, but not to angle of view.


    >>> lot. This year I spent only a few minutea on it. I was stopped by a
    >>> security guard who was worried that I might have a perverted interest
    >>> in photographing child skaters or be planning a terrorist attack.


    >> And next year you'll be arrested for carrying a camera.


    > I doubt it. In the UK over the last few years photographers and
    > lawyers have succeeded in getting the law clarified and better
    > guidelines issued from the government to police and security
    > personnel. That's led to improved relations between photographers,
    > police, and security guards. I used to get harassed often enough that
    > I carried a copy of the relevant legislation in my gear bag. I don't
    > now because there's much less harassment.


    All it takes is just one terrorist that also used a camera once.



    >>> No idea what that argument means.


    >> Basically: If you need to chimp for a rather long time to
    >> find the right settings, you don't know your camera well.


    > I don't. It's a recent acquisition. It takes me at least six months to
    > get to know a camera well. But on the other hand the exposure
    > parameters I'm playing with are in this case largely camera
    > independent.


    And exposure --- unlike preview mode --- carries over well.

    >> If you don't need to chimp for a long time,


    > Which I don't.


    >> I call your
    >> ""sufficiently much faster that in five minutes shooting you
    >> can come away with many more good shots of a much greater
    >> ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
    >> variety than without preview" bull.
    >> ^^^^^^^


    > Experiment trumps speculation. My experiment, your speculation.


    So you did experiment shooting a second five minutes shooting
    without preview mode and came off with many less good shots
    and with a much smaller variety? I doubt that!

    So, let's stay with logic: you'd need to produce many good
    shots and of a much greater variety in the time you'd spend
    with chimping otherwise. I dunno about you, but I can't do many
    *good* shots in 20 seconds. Much less in a very great variety.


    >>> It does you credit that you're worried about the educational state of
    >>> lazy or stupid photographers and would rather the market insisted on
    >>> supplying them with cameras they couldn't work without a proper
    >>> scientific understanding of camera technology.


    >> Where did I require that one enter Maxwell's equations into
    >> the camera before the shutter works? Or alternatively, the
    >> theory of charge transport in semi-conductors? Or maybe how
    >> to design and make a processor for the camera?


    > When you look up "loupe" in your dictionary look up "eristic argument"
    > as well :)


    Yep, it's really a good term for your "cameras they couldn't
    work without a proper scientific understanding of camera
    technology." Thank you.


    >>> Unfortunately the
    >>> market is based on consumer choice.


    >> Really? So where are the cameras many ask for?


    > In the shops.


    So where's the affordable compact camera with a really large
    sensor, 8 or less huge MPix, a good *fast* lens, an optical
    view finder ...


    >>>> So why not leave off the preview mode (instead of wasting
    >>>> months or years on it) and start being in a fix and thus
    >>>> learning immediately? Please use short, simple words to
    >>>> explain that ...


    >>> Because that learning process is less fun, and I'm easily bored. Plus
    >>> preview lets me get a lot more fairly good shots while I'm doing the
    >>> learning. Helps my motivation. I also suspect that learning which is
    >>> more fun works faster and better. But I'm willing to accept that may
    >>> be a personal idiosyncracy.


    >> I see. You want the easiest way, not the fastest or the
    >> best way.


    > Not what I said nor meant. I said I wanted the most fun while
    > learning.


    Yep, the easiest way.

    > By that I meant playful skill acquisition and problem
    > solving. That's always been the best and fastest way to learn for me.
    > A friend and cognitive psychologist tells me that's not just a
    > personal idiosyncrasy of mine.


    "best" and "fastest" are hard to judge, since you cannot
    compare well yourself.

    Funniest/most entertaining way, that's easy to find out.

    -Wolfgang
     
    Wolfgang Weisselberg, Jan 9, 2013
    #43
  4. In rec.photo.digital.slr-systems Wolfgang Weisselberg <> wrote:
    > ["Followup-To:" header set to rec.photo.digital.]
    > Chris Malcolm <> wrote:
    >> In rec.photo.digital Wolfgang Weisselberg <> wrote:
    >>> Chris Malcolm <> wrote:


    >>>> They [previews] usually show you what you'll get. In certain
    >>>> circumstances they don't. You're right that learning what those
    >>>> circumsntaces are, and if an inquisitive person, why, is a good and
    >>>> useful idea. A brief glimpse of the taken shot flashed up on the
    >>>> LCD or EVF will immediately show you the difference between preview
    >>>> prediction and result.


    >>> So you need the same time to assess the correctness of the
    >>> preview mode as you need to check any other parameters.


    >> Not necessarily. For example if the EVF (or LCD panel) is set to show
    >> the resulting image after the shot there is an instant flick between
    >> pre and post views which highlights small differences rapidly &
    >> effectively. Astronomers use that same process to draw the eye to very
    >> small changes which are otherwise imperceptible.


    > Blink comparators switch many times between 2 images, not
    > just once --- for a very good reason. And even then you need
    > perfect alignment *and* no blanking.


    For their purposes, which involve identification of very small changes
    of detail. For the purpose I'm describing the instant switch between
    the two images works well to draw the eye and attention to
    differences. For static subjects alignment is perfect. For moving
    skaters it's good enough to be useful. The blanking is very brief, I
    guess about the same as an OVF DSKR mirror blank, and while I agree it
    would be better with no blanking, there is despite the blank a useful
    comparative effect.

    > Oh, and does your EVF
    > or LCD show 10x magnification of the whole image at once?


    No, neither does my computer monitor no does the optical viewfinders
    in my DSLRs and SLR. Despite that handicap I find them useful. I agree
    that if they were big enough to show the whole image at pixel level
    resolution they'd be even better.

    [snip]

    >>>> [...] It would be nice if our cameras' auto functions were all
    >>>> infallibly perfect, but none of them are, and it's part of any
    >>>> inquisitive and careful photographer's work to find out when they
    >>>> can't be trusted.


    >>> Incorrect. There can be an inquisitive and careful photographer
    >>> who stays with full manual for his work.


    >> True, but the more restricted is the range of inquisitive
    >> investigation the less it deserves the title.


    > Why should someone who investigates what's effective in
    > his photography and doesn't need automatic functions for
    > his work investigate something so unimportant to his work?


    From a purposeful point of view of course they don't. The point is
    that a purposeful point of view is based on assumptions which while
    usually true sometimes turn out to be false. Especially when there are
    changes in the technology. I'm sure you're aware of how many important
    changes in science ocurred when changing technology introduced higher
    data resolution and new possibilities, and how often the consequent
    new ideas and new methods required an unusually open-minded individual
    who noticed something intriguing which all the other experts had
    either been blind to or "knew" was of no significance.

    >> An optical viewfinder shows the image the lens is presenting to the
    >> image sensor. An EVF shows you what the sensor makes of it. An EVF
    >> in preview mode shows you in addition what your selected jpeg
    >> processing options etc. have on the image.


    > An EVF in preview mode *sometimes* show you an image
    > *downsampled to 0.3-0.4 MPix* of what the sensor and JPEG engine
    > made of the light that arrived through the lens *some time ago*
    > on an *uncorrected* monitor that's usually much too bright in
    > low light situations.


    Excellent job of describing an EVF is such a way as to make it sound
    worse than useless. Shame you couldn't find more credible numbers.

    [snip]

    >>>> It's
    >>>> also possible that all kinds of variable eye and brain physiology
    >>>> comes into this and that some people will find the preview facilities
    >>>> far more annoying than useful.


    >>> I would find it plainly impossible to see the difference between
    >>> tack sharp and mostly sharp in preview.


    >> Which I expect is why the facility to magnify the preview image up to
    >> image sensor pixel level was provided.


    > Which again --- with roller skates --- means you need to have
    > your subject pass the part of whatever 0.3 MPix


    There are bigger EVFs than that.

    > you're currently
    > seeing at pixel level and judge in 1/60s (or whatever refresh
    > rate you EVF uses)


    If we're talking preview mode then the refresh rate is the chosen
    shutter speed plus a small constant.

    > if the subject was tack sharp or only mostly
    > sharp --- or reliably follow the subject at that magnification
    > without camera shake or blur from the camera movement.


    You're absolutely right that's what you'd have to do if you were
    trying to judge tack sharpness in preview mode while photgraphing
    moving skaters. I've already explained to you at least twice why I I
    wasn't trying to do anything as silly as that.

    Do you find this poor memory a handicap in everyday life, or does it
    only happen when you're arguing with people in newsgroups?

    [snip]

    >> A nice feature of EVFs is that stopping down the lens doesn't dim the
    >> view unless you want it to. Very handy when doing long tripod
    >> exposures in churches or carefully selecting DoF in interior shots lit
    >> by strobes.


    > Yes, *please* show me how you evaluate the light, the JPEG
    > settings and the DoF in a dark interior shot lit by strobes
    > ... in preview mode!


    Are you deliberately trying to be stupid? Or does it come quite
    naturally to you to have forgotten that *I*'ve already pointed out to
    *you* that evaluating strobe lighting was one of the things EVF
    preview can't possibly do.

    [snip]

    >>>>> Not with any refresh rate that's needed to
    >>>>> even sorta track the subject, and not without a 10x (or more)
    >>>>> loupe, which severely cuts your perception of the scene.


    >>>> A 10x loupe?? Why on earth would you ever need a loupe on a camera
    >>>> which can easily magnify any part of the image,


    >>> That isn't called a loupe?


    >> No. A loupe is a lens. Do you describe zooming in and panning around
    >> when inspecting a large image on your computer monitor as "using a
    >> loupe"? I suggest you look up "loupe" in a dictionary.


    > http://www.gregorybraun.com/Loupe.html
    > http://www.artissoftware.com/screentools/loupe.html
    > http://www.markus-bader.de/MB-Ruler/help/loupe.htm


    > Maybe your dictionary is out of date?


    That's possible, but pretty unlikely in this case. You're certainly
    not going to convince me that it is by citing product advertisements
    which only use the word in a specifically qualified phrase. That you
    even bother doing that strongly suggests that you know even less about
    dictionaries than you know about EVFs.

    >>> If you don't want more than sorta-WYSIWYG, preview mode only,
    >>> then that's perfectly fine with me, use preview mode, stay
    >>> with preview mode.


    >>> But you cannot transfer what you learn there to other modes,
    >>> not without deliberately and consciously working on it.
    >>> In other modes you can't get away ignoring the numbers and
    >>> their meanings --- you learn by default.


    >> But underneath the image are displayed the shutter speed, aperture,
    >> ISO, plus a lot more which you can choose whether or not to display.


    > And on web pages there are ad banners on the top and on each
    > site. They're habitually ignored.


    There you go again. I'm explaining to you what *I* do with certain
    bits of photographic technology and why. I don't give a damn what
    other people do with it. I want to know those numbers, and they're
    conveniently displayed alongside the image. Good. I don't give a hoot
    that people who don't want to know the numbers will ignore them.

    > On Windows, there are many cases where you need to confirm a
    > detrimental action. But as such pop ups are used for
    > everything, people are conditioned to ignore the warning that
    > they destroy their installation and click OK.


    So what? I make no claim that my camera or my methods are good
    educational tools for forcing the lazy and ignorant to learn. I don't
    even give a damn if they're worse than useless at forcing education on
    the unwilling. The educational fate of the incurious is not something
    that influences my choices of camera technology.

    > Just having the numbers doesn't mean that they're being seen.


    So what? When I let my camera choose aperture, shutter speed, or ISO,
    I want to know what it's chosen. I don't give a damn if other people
    ignore the information.

    >> That facilitates the learning if learning is what you want to do. You
    >> might be right that it also helps you to avoid learning if that's what
    >> you want to do.


    > In your skater example, did you look at the numbers, adjusted
    > them and then checked the effect, or did you turn the dials
    > till the effect was sorta what you wanted and then looked at
    > the numbers? (Or did you ignore the numbers completely?)


    Haven't I already explained that? I did both of the first two in that
    order.

    [snip]

    >>>> I do know about the
    >>>> reciprocal of the focal length for shutter speed, that you have to
    >>>> adapt that to digital sensor size and resolution, add in the image
    >>>> stabilising factor when appropriate, adapt it to the holding method
    >>>> employed (e.g. elbows on wall, monopod, tripod), factor in wind,
    >>>> factor in unusual rotational inertias (e.g. long reflective vs
    >>>> refractive lens), etc etc.


    >>> Yep. So how many bodies and lenses do you regularly use?


    >> Depepnding on how you define "regularly" anywhere between five and ten
    >> lenses. I'm not counting lenses I use less than once a year. I usually
    >> carry at least three. I only use my backup camera when I want to
    >> reduce lens changes. It doesn't do anything better than my best camera
    >> so it never goes out alone. That varies between more than once a week
    >> to less than once a month so I wouldn't call my use of two bodies
    >> regular.


    > Do your know your regular lenses well?


    Yes. How about you? How many bodies and lenses do you regularly use?
    How well do you know your lenses?

    >>> Really? I try a new technique, I see what comes out, I
    >>> adjust as necessary to my goal, I remember what works and
    >>> what not for next time.


    >> Sounds like you're blessed with a much better memory than I've ever
    >> had. I sometimes solve a problem on the run in a busy shoot and by the
    >> time I get to reviewing the results on the computer I've forgotten how
    >> I did it.


    > You don't have EXIF in your files? There's everything in
    > there that you can influence by using the preview mode ...


    You really think that? You mean all your lenses are fully automated?
    There's an unexpected surprise! Plus even with fully automated lenses
    all that's recorded is what's settable. That may be only part of
    what's necessary to understanding how the problem was solved.

    [snip]

    >>> Action shooters generally do not employ preview mode, though:
    >>> they don't want the additional *variable* lag between photons
    >>> hitting the sensor and dots lighting up on the EVF.


    >> Of course. In that case you'd either avoid using the laggier kinds of
    >> EVF processing or avoid preview mode altogether. The fastest and most
    >> difficult kind of action shooting I do is birds in flight with a 500mm
    >> lens and for that I don't use the camera's viewfinder at all. I use an
    >> adapted gunsight which lets me use both eyes on the whole scene.


    > Yet wouldn't it be perfect if you used preview mode to have
    > the body tack sharp but the tips of the wings blurred to
    > show the dynamic movement?


    I don't see the point. If the technology somehow offered that then
    human eyes and hands are way too slow to be able to use it.

    >>>>> Much easier to freeze one frame and evaluate it at leisure,
    >>>>> once you have a rough idea (which requires about as much
    >>>>> training as using the preview properly) --- and exactly that
    >>>>> is what happens when you take a shot.


    >>>> That is indeed much easier, but sometimes there isn't time to do that.


    >>> Then there isn't time to play with preview modes either.


    >> Not my experience. I find I still have time to use preview when
    >> there's no time to shoot and review. It's better at that than I
    >> expected before trying it.


    > That would mean lots of experience with preview, but low on
    > experience with exposure times and apertures.


    You must be making some seriously false assumptions then. My
    experience with preview is a few months of elapsed time and a few
    hundred photographs.

    Whereas I spent fifteen years and thousands of photographs with fully
    manual cameras before I started using cameras with either autofocus or
    autoexposure. I still regularly use at least two fully manual lenses,
    plus all but one of my flashguns are only manual, and I still usually
    an exposure meter in my gear bag. So my experience of exposure times
    and apertures hugely outweighs my experience of preview mode, and is
    still being refreshed and improved by being in regular use.

    >>>>> SURE, if you have NO idea at all, then a preview helps ---


    >>>> I find it also helps in my case where I have quite a good idea, having
    >>>> learned my photgraphy back in the old days before there was even
    >>>> autoexposure let alone autofocus.


    >>> You're saying you're still surprised by aperture or exposure
    >>> time settings?


    >> Surprised is too strong a word. But where there are conflicting
    >> demands and aesthetic trade offs involved I like to experiment with
    >> different compromises. Anything which shortens the time between
    >> experiment and result is useful, especially when the shortening steps
    >> over the important boundary between experiment and check into
    >> interactive process control.


    > The best shortening would be knowing pretty well which
    > combination work.


    Of course. Iterative approximation is always greatly helped by being
    able to start with a good estimate.

    > It's sorta like phase AF and contrast AF:
    > Phase AF knows the direction and (quite exact) the amount
    > of travel, contrast AF is an interactive control process ...
    > guess which one is still faster.


    As usual it's the one which is least accurate. I'm pleased to see that
    my latest camera has two phase based autofocus speeds. The slower one
    is a bit more reliably accurate despite being faster than the single
    AF speed of my previous camera.

    I'm disappointed that it doesn't offer three AF speeds, where the
    third and slowest would be a final tuning of the phase based autofocus
    by contrast based. A deliberate slight undershoot of the phase-based
    AF would solve the contrast based focus direction problem.

    [snip]

    >> But if you're referring to learning and experience which is specific
    >> to certain makes and models of camera you're right.


    > Exactly.
    > You learn --- and then have to throw away most of it when you
    > change cameras.


    Not my experience at all. I'm beginning to wonder just how much you've
    learned about these newfangled technologies you don't like. The
    biggest technology shift I've ever made was the shift from film to
    digital. But even then I didn't have to throw most of what I'd learned
    away. Even some film darkroom technique knowledge carried over into
    the digital darkroom of computer post processing.

    >> That lack of
    >> generality is also true of autofocus. That doesn't stop autofocus
    >> being very useful, nor does it stop it being useful to learn exactly
    >> how a specific kind of autofocus technology works and where and why it
    >> fails.


    > AF is fully automatic.


    If you're suggesting that it works so well that you don't need to
    understand how it works in order to understand how and why it fails
    than you're a much less sophisticated photographer than I took you
    for. There's a reason why the top end cameras with the best AF also
    have the best aids to rapid and accurate manual focusing, plus the
    ability to do lens speciofic microfovus adjustments.

    There are also degrees of "fully automatic".

    My new camera has a nice AF mode which drops into manual focus mode
    once AF has locked. That allows me to check and if necessary adjust
    focus manually without having to press any buttons. That's also an
    inherent feature of some of the latest in-lens focus drives, but this
    camera AF mode applies to all AF lenses of any vintage. So even though
    the new camera has got the best AF I've used so far, I'm using manual
    focus more often because it's now easier and faster than before.

    > Full auto mode is fully automatic.


    Depends what you mean by full. On my previous camera full auto meant
    the camera chose aperture, shutter, and ISO. When using full auto the
    user could select various modes, such as sports, which went for action
    freezing shutter speeds, or landscape, which went for lowest
    ISOs. etc.. Whereas my new camera has two auto modes, the fuller of
    which selects the mode based on looking at the image. e.g. it will
    select sports mode if there are large fast moving things in view.

    > Preview is fully manual. And slower than full auto.


    There wouldn't be much point to auto modes which were slower than
    manual. The point about manual adjustment is being able to make more
    sophisticated and accurate choices than auto is capable of. The point
    of an optional preview mode is that in some circumstances it lets you
    make your manual choices more easily and faster, which can bring the
    extra sophistication of manual into faster kinds of photography.

    >>>>> Which means the
    >>>>> knowledge doesn't carry over.


    >>>> Your arguments are much too black and white. That not all the
    >>>> knowledge carries over doesn't mean that none of it does. All the
    >>>> knowledge doesn't carry over. But a useful amount of it does.


    >>> Yet with aperture and exposure time almost all carries over,
    >>> even switching sensor sizes.


    >> A surprising amount of what I learned in my film shooting days has
    >> turned out to have been oversimplified and overgeneralised. That's
    >> mainly been due to increasing sensor resolution revealing unsuspected
    >> problems in earlier cruder generalisations. Rather like the way
    >> improved detail resolution in scientific measuring instruments reveals
    >> the simplifications and overgeneralisations in earlier mathematical
    >> models.


    > Naah. You've increased the enlargement (you print larger or
    > look at 100% with higher resolutions), you needed to factor
    > that in even back when.


    You're ignoring the fact that increased resolution often splits apart
    things which were previously confounded because they couldn't be
    distinguished. For example with film cameras I never noticed the
    differences between mirror shake and shutter shake in image
    blurring. I put it all down to mirror. Whereas the increased detail
    resolution which digital photography gave me allowed me to see the
    differences for the first time. (I know some people measured shutter
    shake back in film days. But I couldn't see it my photographs and
    considered it to be trivially insignificant.)

    > What has changed is that you are more variable in your ways.
    > But luckily all you need is a simple correction factor.


    Luckily it's a lot more complex than that. I say luckily, because if
    it was just correction factors I'd find it much less interesting.

    >>>> In fact angle of view is more independent and useful than
    >>>> "equivalent focal length" which IMHO is a silly fudge of an incomplete
    >>>> generalisation.


    >>> So you'd write an angle of view on a lens --- which is then
    >>> attached to a 35mm-sized sensor, a 1.6x crop sensor, a 2x crop
    >>> MFT and maybe even to a 2.7x '1"' sensor. For which sensor
    >>> would you write the angle of view?


    >> None, for exactly the same reasons I wouldn't write "equivalent focal
    >> length" on a lens either.


    > Thus the focal length is most useful, and from there you get
    > trivially to equivalent focal length, but not to angle of view.


    I don't see why calculating equivalent focal length is more trivial
    than calculating view angle. Nor do I see why it's more useful to me
    (obviously YMMV). For example in off-site planning of shots of
    building exteriors and interiors I've much more often decided I wanted
    a specific view angle, and then had to calculate what focal length I'd
    need, than the reverse.

    [snip]

    >>> I call your
    >>> ""sufficiently much faster that in five minutes shooting you
    >>> can come away with many more good shots of a much greater
    >>> ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
    >>> variety than without preview" bull.
    >>> ^^^^^^^


    >> Experiment trumps speculation. My experiment, your speculation.


    > So you did experiment shooting a second five minutes shooting
    > without preview mode and came off with many less good shots
    > and with a much smaller variety? I doubt that!


    No, I didn't do that experiment. I've already described the experiment
    I did. The results were qualitatively similar to the results a number
    of others have reported when doing their own comparative assessments.

    [snip]

    >>>> Unfortunately the
    >>>> market is based on consumer choice.


    >>> Really? So where are the cameras many ask for?


    >> In the shops.


    > So where's the affordable compact camera with a really large
    > sensor, 8 or less huge MPix, a good *fast* lens, an optical
    > view finder ...


    And plenty of people want Porsche performance at Volkwagen Beetle
    prices. I wonder why the car makers aren't making that obvious best
    seller? Must be some kind of conspiracy against the customer...

    --
    Chris Malcolm
     
    Chris Malcolm, Jan 11, 2013
    #44
  5. Chris Malcolm <> wrote:
    > In rec.photo.digital.slr-systems Wolfgang Weisselberg <> wrote:
    >> ["Followup-To:" header set to rec.photo.digital.]
    >> Chris Malcolm <> wrote:
    >>> In rec.photo.digital Wolfgang Weisselberg <> wrote:
    >>>> Chris Malcolm <> wrote:


    >>>>> They [previews] usually show you what you'll get. In certain
    >>>>> circumstances they don't. You're right that learning what those
    >>>>> circumsntaces are, and if an inquisitive person, why, is a good and
    >>>>> useful idea. A brief glimpse of the taken shot flashed up on the
    >>>>> LCD or EVF will immediately show you the difference between preview
    >>>>> prediction and result.


    >>>> So you need the same time to assess the correctness of the
    >>>> preview mode as you need to check any other parameters.


    >>> Not necessarily. For example if the EVF (or LCD panel) is set to show
    >>> the resulting image after the shot there is an instant flick between
    >>> pre and post views which highlights small differences rapidly &
    >>> effectively. Astronomers use that same process to draw the eye to very
    >>> small changes which are otherwise imperceptible.


    >> Blink comparators switch many times between 2 images, not
    >> just once --- for a very good reason. And even then you need
    >> perfect alignment *and* no blanking.


    > For their purposes, which involve identification of very small changes
    > of detail.


    20 MPix on a 0.3 MPix screen (1MDot): each *single* pixel is
    66 pixel in the original. Rather large changes in the original
    are there very small changes of detail.

    > For the purpose I'm describing the instant switch between
    > the two images works well to draw the eye and attention to
    > differences.


    If the change is well visible and comparatively large.

    > For static subjects alignment is perfect.


    But for static subjects you have all the time in the world
    to try settings and chimp and don't need a preview mode.

    > For moving
    > skaters it's good enough to be useful. The blanking is very brief, I
    > guess about the same as an OVF DSKR mirror blank, and while I agree it
    > would be better with no blanking, there is despite the blank a useful
    > comparative effect.


    Which means you'll only percive large changes ...

    >> Oh, and does your EVF
    >> or LCD show 10x magnification of the whole image at once?


    > No, neither does my computer monitor no does the optical viewfinders
    > in my DSLRs and SLR.


    Neither of them are 0.3 MPix only ... and in the case of a
    computer monitor it's extremely hard to zoom in and view
    small details, don't you think so?

    > Despite that handicap I find them useful. I agree
    > that if they were big enough to show the whole image at pixel level
    > resolution they'd be even better.


    Optical view finders come closest to that.

    >>>>> [...] It would be nice if our cameras' auto functions were all
    >>>>> infallibly perfect, but none of them are, and it's part of any
    >>>>> inquisitive and careful photographer's work to find out when they
    >>>>> can't be trusted.


    >>>> Incorrect. There can be an inquisitive and careful photographer
    >>>> who stays with full manual for his work.


    >>> True, but the more restricted is the range of inquisitive
    >>> investigation the less it deserves the title.


    >> Why should someone who investigates what's effective in
    >> his photography and doesn't need automatic functions for
    >> his work investigate something so unimportant to his work?


    > From a purposeful point of view of course they don't. The point is
    > that a purposeful point of view is based on assumptions which while
    > usually true sometimes turn out to be false. Especially when there are
    > changes in the technology. I'm sure you're aware of how many important
    > changes in science ocurred when changing technology introduced higher
    > data resolution and new possibilities, and how often the consequent
    > new ideas and new methods required an unusually open-minded individual
    > who noticed something intriguing which all the other experts had
    > either been blind to or "knew" was of no significance.


    And what "changes in science" would be analogus to the changes
    pertaining to fully manual operation, and wouldn't your answer
    be akin to telling all photographs to better learn optics and
    electronics and quantum physics since they all are relevant
    to digital photography, and to learn computer science and
    algorithms since they directly pertain to the digital dark room?

    >>> An optical viewfinder shows the image the lens is presenting to the
    >>> image sensor. An EVF shows you what the sensor makes of it. An EVF
    >>> in preview mode shows you in addition what your selected jpeg
    >>> processing options etc. have on the image.


    >> An EVF in preview mode *sometimes* show you an image
    >> *downsampled to 0.3-0.4 MPix* of what the sensor and JPEG engine
    >> made of the light that arrived through the lens *some time ago*
    >> on an *uncorrected* monitor that's usually much too bright in
    >> low light situations.


    > Excellent job of describing an EVF is such a way as to make it sound
    > worse than useless.


    Well, I can't help if they are near worse than useless.
    If you'd manage to reduce the drawbacks *a lot* it may become
    viable. Battery eating, but viable.

    > Shame you couldn't find more credible numbers.


    Tell me, how many dots do your EVFs have ... then we have a
    credible number!

    >>>>> It's
    >>>>> also possible that all kinds of variable eye and brain physiology
    >>>>> comes into this and that some people will find the preview facilities
    >>>>> far more annoying than useful.


    >>>> I would find it plainly impossible to see the difference between
    >>>> tack sharp and mostly sharp in preview.


    >>> Which I expect is why the facility to magnify the preview image up to
    >>> image sensor pixel level was provided.


    >> Which again --- with roller skates --- means you need to have
    >> your subject pass the part of whatever 0.3 MPix


    > There are bigger EVFs than that.


    Really? How many dots is your's?

    >> you're currently
    >> seeing at pixel level and judge in 1/60s (or whatever refresh
    >> rate you EVF uses)


    > If we're talking preview mode then the refresh rate is the chosen
    > shutter speed plus a small constant.


    Nope. The EVF can't update at infinite speeds. The sensor
    cannot be read at infinite speeds. Even if the light is only
    captured for a 1/4000s, that doesn't mean the refresh rate
    is in the 1000's per second.

    Same with your LCD screen. Your game may do 300 fps, but
    your screen does 60Hz ...


    >> if the subject was tack sharp or only mostly
    >> sharp --- or reliably follow the subject at that magnification
    >> without camera shake or blur from the camera movement.


    > You're absolutely right that's what you'd have to do if you were
    > trying to judge tack sharpness in preview mode while photgraphing
    > moving skaters. I've already explained to you at least twice why I I
    > wasn't trying to do anything as silly as that.


    So you never would want a moving skater tack sharp, you say?

    > Do you find this poor memory a handicap in everyday life, or does it
    > only happen when you're arguing with people in newsgroups?


    It's more likely my writing skill, since you obviously can
    divine everything someone else writes.


    >>> A nice feature of EVFs is that stopping down the lens doesn't dim the
    >>> view unless you want it to. Very handy when doing long tripod
    >>> exposures in churches or carefully selecting DoF in interior shots lit

    ^^^
    >>> by strobes.

    ^^^^^^^^^^^

    >> Yes, *please* show me how you evaluate the light, the JPEG
    >> settings and the DoF in a dark interior shot lit by strobes
    >> ... in preview mode!


    > Are you deliberately trying to be stupid?


    No, just reading what you write.

    > Or does it come quite
    > naturally to you to have forgotten that *I*'ve already pointed out to
    > *you* that evaluating strobe lighting was one of the things EVF
    > preview can't possibly do.


    So you do DoF in interior shots by pushing the ISO to so high
    the noise precludes you from seeing really sharp --- huh, wait
    a moment, you're right! It doesn't matter on VGA resolution!
    (Not that you can judge DoF very well there ...)


    >>>>>> Not with any refresh rate that's needed to
    >>>>>> even sorta track the subject, and not without a 10x (or more)
    >>>>>> loupe, which severely cuts your perception of the scene.


    >>>>> A 10x loupe?? Why on earth would you ever need a loupe on a camera
    >>>>> which can easily magnify any part of the image,


    >>>> That isn't called a loupe?


    >>> No. A loupe is a lens. Do you describe zooming in and panning around
    >>> when inspecting a large image on your computer monitor as "using a
    >>> loupe"? I suggest you look up "loupe" in a dictionary.


    >> http://www.gregorybraun.com/Loupe.html
    >> http://www.artissoftware.com/screentools/loupe.html
    >> http://www.markus-bader.de/MB-Ruler/help/loupe.htm


    >> Maybe your dictionary is out of date?


    > That's possible, but pretty unlikely in this case. You're certainly
    > not going to convince me that it is by citing product advertisements
    > which only use the word in a specifically qualified phrase. That you
    > even bother doing that strongly suggests that you know even less about
    > dictionaries than you know about EVFs.


    Obviously you know everything and need to tell others they
    don't know anything.


    >>>> If you don't want more than sorta-WYSIWYG, preview mode only,
    >>>> then that's perfectly fine with me, use preview mode, stay
    >>>> with preview mode.


    >>>> But you cannot transfer what you learn there to other modes,
    >>>> not without deliberately and consciously working on it.
    >>>> In other modes you can't get away ignoring the numbers and
    >>>> their meanings --- you learn by default.


    >>> But underneath the image are displayed the shutter speed, aperture,
    >>> ISO, plus a lot more which you can choose whether or not to display.


    >> And on web pages there are ad banners on the top and on each
    >> site. They're habitually ignored.


    > There you go again. I'm explaining to you what *I* do with certain
    > bits of photographic technology and why.


    *I* can do without preview mode, make of that what you like.

    > I don't give a damn what
    > other people do with it. I want to know those numbers, and they're
    > conveniently displayed alongside the image. Good. I don't give a hoot
    > that people who don't want to know the numbers will ignore them.


    Oh well, it only takes enough people who don't give a hoot
    for what other people do ...


    >> On Windows, there are many cases where you need to confirm a
    >> detrimental action. But as such pop ups are used for
    >> everything, people are conditioned to ignore the warning that
    >> they destroy their installation and click OK.


    > So what? I make no claim that my camera or my methods are good
    > educational tools for forcing the lazy and ignorant to learn.


    I don't care about forcing anyone. I care about people being
    sucked into dead ends.

    > I don't
    > even give a damn if they're worse than useless at forcing education on
    > the unwilling.


    Do you have fun misrepresenting my position? If I wanted to
    force educatiuon I'd be on the barricades against full auto
    modes ...

    > The educational fate of the incurious is not something
    > that influences my choices of camera technology.


    The idea that all valuable people are naturally curios and
    there's no need for directed learning is proven by the fact
    that most countries have stopped having schools.


    >> Just having the numbers doesn't mean that they're being seen.


    > So what? When I let my camera choose aperture, shutter speed, or ISO,
    > I want to know what it's chosen. I don't give a damn if other people
    > ignore the information.


    Straw man: you don't let the camera choose with preview mode.

    >>>>> I do know about the
    >>>>> reciprocal of the focal length for shutter speed, that you have to
    >>>>> adapt that to digital sensor size and resolution, add in the image
    >>>>> stabilising factor when appropriate, adapt it to the holding method
    >>>>> employed (e.g. elbows on wall, monopod, tripod), factor in wind,
    >>>>> factor in unusual rotational inertias (e.g. long reflective vs
    >>>>> refractive lens), etc etc.


    >>>> Yep. So how many bodies and lenses do you regularly use?


    >>> Depepnding on how you define "regularly" anywhere between five and ten
    >>> lenses. I'm not counting lenses I use less than once a year. I usually
    >>> carry at least three. I only use my backup camera when I want to
    >>> reduce lens changes. It doesn't do anything better than my best camera
    >>> so it never goes out alone. That varies between more than once a week
    >>> to less than once a month so I wouldn't call my use of two bodies
    >>> regular.


    >> Do your know your regular lenses well?


    > Yes. How about you? How many bodies and lenses do you regularly use?
    > How well do you know your lenses?


    Not as many lenses as you use, but I think I know my lenses
    fairly well.

    >>>> Really? I try a new technique, I see what comes out, I
    >>>> adjust as necessary to my goal, I remember what works and
    >>>> what not for next time.


    >>> Sounds like you're blessed with a much better memory than I've ever
    >>> had. I sometimes solve a problem on the run in a busy shoot and by the
    >>> time I get to reviewing the results on the computer I've forgotten how
    >>> I did it.


    >> You don't have EXIF in your files? There's everything in
    >> there that you can influence by using the preview mode ...


    > You really think that? You mean all your lenses are fully automated?


    So how come your preview mode shows the aperture on your
    manual lenses?

    > There's an unexpected surprise! Plus even with fully automated lenses
    > all that's recorded is what's settable. That may be only part of
    > what's necessary to understanding how the problem was solved.


    And what does preview mode do better for directing/adjusting/
    adding light? Or for correcting the composition? Or for
    using a lens hood? Or using makeup on the models?


    >>>> Action shooters generally do not employ preview mode, though:
    >>>> they don't want the additional *variable* lag between photons
    >>>> hitting the sensor and dots lighting up on the EVF.


    >>> Of course. In that case you'd either avoid using the laggier kinds of
    >>> EVF processing or avoid preview mode altogether. The fastest and most
    >>> difficult kind of action shooting I do is birds in flight with a 500mm
    >>> lens and for that I don't use the camera's viewfinder at all. I use an
    >>> adapted gunsight which lets me use both eyes on the whole scene.


    >> Yet wouldn't it be perfect if you used preview mode to have
    >> the body tack sharp but the tips of the wings blurred to
    >> show the dynamic movement?


    > I don't see the point. If the technology somehow offered that then
    > human eyes and hands are way too slow to be able to use it.


    I can think of several easy ways to allow that for people who
    can see moving skaters blurred with preview mode, apart from
    simply finding out the right combinations.


    >>>>>> Much easier to freeze one frame and evaluate it at leisure,
    >>>>>> once you have a rough idea (which requires about as much
    >>>>>> training as using the preview properly) --- and exactly that
    >>>>>> is what happens when you take a shot.


    >>>>> That is indeed much easier, but sometimes there isn't time to do that.


    >>>> Then there isn't time to play with preview modes either.


    >>> Not my experience. I find I still have time to use preview when
    >>> there's no time to shoot and review. It's better at that than I
    >>> expected before trying it.


    >> That would mean lots of experience with preview, but low on
    >> experience with exposure times and apertures.


    > You must be making some seriously false assumptions then. My
    > experience with preview is a few months of elapsed time and a few
    > hundred photographs.


    Which means --- since you are a curious person and make every
    shot count --- you have lots of experience.

    > Whereas I spent fifteen years and thousands of photographs with fully
    > manual cameras before I started using cameras with either autofocus or
    > autoexposure. I still regularly use at least two fully manual lenses,
    > plus all but one of my flashguns are only manual, and I still usually
    > an exposure meter in my gear bag. So my experience of exposure times
    > and apertures hugely outweighs my experience of preview mode, and is
    > still being refreshed and improved by being in regular use.


    But you still don't hit the right combinations from experience,
    thus you need preview mode to be fast.


    >>>>>> SURE, if you have NO idea at all, then a preview helps ---


    >>>>> I find it also helps in my case where I have quite a good idea, having
    >>>>> learned my photgraphy back in the old days before there was even
    >>>>> autoexposure let alone autofocus.


    >>>> You're saying you're still surprised by aperture or exposure
    >>>> time settings?


    >>> Surprised is too strong a word. But where there are conflicting
    >>> demands and aesthetic trade offs involved I like to experiment with
    >>> different compromises. Anything which shortens the time between
    >>> experiment and result is useful, especially when the shortening steps
    >>> over the important boundary between experiment and check into
    >>> interactive process control.


    >> The best shortening would be knowing pretty well which
    >> combination work.


    > Of course. Iterative approximation is always greatly helped by being
    > able to start with a good estimate.


    Getting a good estimate in this case means remembering what
    worked and what didn't.


    >> It's sorta like phase AF and contrast AF:
    >> Phase AF knows the direction and (quite exact) the amount
    >> of travel, contrast AF is an interactive control process ...
    >> guess which one is still faster.


    > As usual it's the one which is least accurate.


    Go read
    http://www.lensrentals.com/blog/2012/08/autofocus-reality-part-3b-canon-cameras
    and find out that that and why that isn't true in all cases
    anymore ...

    > I'm pleased to see that
    > my latest camera has two phase based autofocus speeds. The slower one
    > is a bit more reliably accurate despite being faster than the single
    > AF speed of my previous camera.


    > I'm disappointed that it doesn't offer three AF speeds, where the
    > third and slowest would be a final tuning of the phase based autofocus
    > by contrast based. A deliberate slight undershoot of the phase-based
    > AF would solve the contrast based focus direction problem.


    Use an extender and it'll be slower.


    >>> But if you're referring to learning and experience which is specific
    >>> to certain makes and models of camera you're right.


    >> Exactly.
    >> You learn --- and then have to throw away most of it when you
    >> change cameras.


    > Not my experience at all.


    So you say preview mode carries over?

    > I'm beginning to wonder just how much you've
    > learned about these newfangled technologies you don't like.


    I'm beginning to wonder if I've stopped being able to write
    English. "these newfangled technologies", indeed, probably
    everything that's been invented since just after 2982 BCE,
    when one reads you.


    >>> That lack of
    >>> generality is also true of autofocus. That doesn't stop autofocus
    >>> being very useful, nor does it stop it being useful to learn exactly
    >>> how a specific kind of autofocus technology works and where and why it
    >>> fails.


    >> AF is fully automatic.


    > If you're suggesting that it works so well that you don't need to
    > understand how it works in order to understand how and why it fails
    > than you're a much less sophisticated photographer than I took you
    > for.


    As I said, it seems I'm unable to get you to understand what I am
    saying. Let's try again:
    - AF is a fully automatic system, therefore it has a great
    excuse why it's camera exclusive and needs to be learned for
    full usage. Additionally, it's now much faster than almost
    all human photographers.
    - Preview mode is of very little use on fully automatic
    settings. Now, if exposure time and aperture behaves
    differently between cameras, say one camera being slow and
    the other having a wider aperture ....

    > There's a reason why the top end cameras with the best AF also
    > have the best aids to rapid and accurate manual focusing,


    So which top end cameras have split prismas and microfocus
    rings in their focussing screens?

    > plus the
    > ability to do lens speciofic microfovus adjustments.


    Just like, say, they have manual mode?

    > There are also degrees of "fully automatic".


    > My new camera has a nice AF mode which drops into manual focus mode
    > once AF has locked.


    Your old camera was ancient? One-shot AF is a really old hat.


    >> Full auto mode is fully automatic.


    > Depends what you mean by full.


    Well, go look the word up in a dictionary.

    > On my previous camera full auto meant
    > the camera chose aperture, shutter, and ISO. When using full auto the
    > user could select various modes, such as sports, which went for action
    > freezing shutter speeds, or landscape, which went for lowest
    > ISOs. etc..


    Scene modes are not full auto modes, as the scene type is
    selected by the user.


    >> Preview is fully manual. And slower than full auto.


    > There wouldn't be much point to auto modes which were slower than
    > manual.


    That is a rather limited view.

    > The point about manual adjustment is being able to make more
    > sophisticated and accurate choices than auto is capable of.


    Wrong. The point is making a choice that isn't the most common
    choice given all the camera knows about you and this specific
    situation --- which, short of mind reading, is the best bet
    the camera can make.

    > The point
    > of an optional preview mode is that in some circumstances it lets you
    > make your manual choices more easily and faster,


    The choices are not easier. Choose a change, twirl a knob.
    There you are, made your choice.

    > which can bring the
    > extra sophistication of manual into faster kinds of photography.


    Assuming you can see the change on your low resolution EVF or
    screen ... and you cannot see the change without preview mode.

    >>>>>> Which means the
    >>>>>> knowledge doesn't carry over.


    >>>>> Your arguments are much too black and white. That not all the
    >>>>> knowledge carries over doesn't mean that none of it does. All the
    >>>>> knowledge doesn't carry over. But a useful amount of it does.


    >>>> Yet with aperture and exposure time almost all carries over,
    >>>> even switching sensor sizes.


    >>> A surprising amount of what I learned in my film shooting days has
    >>> turned out to have been oversimplified and overgeneralised. That's
    >>> mainly been due to increasing sensor resolution revealing unsuspected
    >>> problems in earlier cruder generalisations. Rather like the way
    >>> improved detail resolution in scientific measuring instruments reveals
    >>> the simplifications and overgeneralisations in earlier mathematical
    >>> models.


    >> Naah. You've increased the enlargement (you print larger or
    >> look at 100% with higher resolutions), you needed to factor
    >> that in even back when.


    > You're ignoring the fact that increased resolution often splits apart
    > things which were previously confounded because they couldn't be
    > distinguished.


    What part of "increased the enlargement" didn't you get and
    how comes that even on film people used tripods with large
    format, where the resolution is higher?

    > For example with film cameras I never noticed the
    > differences between mirror shake and shutter shake in image
    > blurring. I put it all down to mirror. Whereas the increased detail
    > resolution which digital photography gave me allowed me to see the
    > differences for the first time.


    Duh. How comes that you can see the difference? You enlarge
    more. You could have seen it with film, if your film had had
    high enough resolution to support that kind of enlargement.

    And if you only enlarge as much as you can sensibly with
    film ... can you still see the difference?


    >> What has changed is that you are more variable in your ways.
    >> But luckily all you need is a simple correction factor.


    > Luckily it's a lot more complex than that. I say luckily, because if
    > it was just correction factors I'd find it much less interesting.


    The thing that's complex is how to archive the tighter
    tolerances allowed for the enlargements.


    >>>>> In fact angle of view is more independent and useful than
    >>>>> "equivalent focal length" which IMHO is a silly fudge of an incomplete
    >>>>> generalisation.


    >>>> So you'd write an angle of view on a lens --- which is then
    >>>> attached to a 35mm-sized sensor, a 1.6x crop sensor, a 2x crop
    >>>> MFT and maybe even to a 2.7x '1"' sensor. For which sensor
    >>>> would you write the angle of view?


    >>> None, for exactly the same reasons I wouldn't write "equivalent focal
    >>> length" on a lens either.


    >> Thus the focal length is most useful, and from there you get
    >> trivially to equivalent focal length, but not to angle of view.


    > I don't see why calculating equivalent focal length is more trivial
    > than calculating view angle.


    Quick: Crop factor 1.5. Focal lengths are 34mm, 62mm, 93mm.
    What are the equivalent focal lengths?
    What are the view angles?

    Which one did you get faster?

    > Nor do I see why it's more useful to me
    > (obviously YMMV). For example in off-site planning of shots of
    > building exteriors and interiors I've much more often decided I wanted
    > a specific view angle, and then had to calculate what focal length I'd
    > need, than the reverse.


    OK, that is a special case.


    >>>> I call your
    >>>> ""sufficiently much faster that in five minutes shooting you
    >>>> can come away with many more good shots of a much greater
    >>>> ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
    >>>> variety than without preview" bull.
    >>>> ^^^^^^^


    >>> Experiment trumps speculation. My experiment, your speculation.


    >> So you did experiment shooting a second five minutes shooting
    >> without preview mode and came off with many less good shots
    >> and with a much smaller variety? I doubt that!


    > No, I didn't do that experiment. I've already described the experiment
    > I did.


    Yep, you did. It does in no way support your conclusion.

    > The results were qualitatively similar to the results a number
    > of others have reported when doing their own comparative assessments.


    You didn't do a comparative assessment.


    >>>>> Unfortunately the
    >>>>> market is based on consumer choice.


    >>>> Really? So where are the cameras many ask for?


    >>> In the shops.


    >> So where's the affordable compact camera with a really large
    >> sensor, 8 or less huge MPix, a good *fast* lens, an optical
    >> view finder ...


    > And plenty of people want Porsche performance at Volkwagen Beetle
    > prices.


    Well, were are the cameras for Porsche prices?


    > I wonder why the car makers aren't making that obvious best
    > seller? Must be some kind of conspiracy against the customer...


    Blah blah.

    Let's ask another one: Where is the fully programmable DSLR?

    -Wolfgang
     
    Wolfgang Weisselberg, Jan 16, 2013
    #45
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