Re: Super-Zoom P&S Camera Beats DSLR (again) - Film at 11

Discussion in 'Digital Photography' started by Ray Fischer, Nov 23, 2008.

  1. Ray Fischer

    Ray Fischer Guest

    ReplyingToFools <> wrote:
    >On Sun, 23 Nov 2008 13:22:10 -0500, Stephen Bishop <> wrote:
    >
    >>Ever hear the phrase, "Jack of all trades, master of none?" A dslr
    >>is a specialized tool that can be configured for whatever you need,
    >>and it will do a much better job than any "do everything" portable
    >>camera.

    >
    >Ever hear the phrase: "If even 5 billion people are saying and believing a
    >foolish thing, it remains a foolish thing" ?
    >
    >You fail to realize, a good P&S camera is both hammer and screw-driver, as well
    >as an excellent macro-scope, video-cam, CD-quality stereo sound recorder,
    >thermometer (CHDK cameras also tell you the temperature and time, yes, it's
    >true), etc. etc. etc. Just because one camera can do it all doesn't mean it does
    >them all with lesser quality.


    Yes, it does mean that.

    --
    Ray Fischer
     
    Ray Fischer, Nov 23, 2008
    #1
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  2. Ray Fischer

    John A. Guest

    On Sun, 23 Nov 2008 15:55:27 -0600, AlderWeathermore
    <> wrote:

    >Smaller lenses are easier to manufacture to exacting curvatures and are more
    >easily corrected for aberrations than larger glass used for DSLRs


    Uh, yeah. That's why scale models are always *so* much more highly
    detailed than the full-size originals. :/
     
    John A., Nov 24, 2008
    #2
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  3. Ray Fischer

    Ray Fischer Guest

    ChaseOslo <coslo@.org> wrote:
    > John A.


    >>>Smaller lenses are easier to manufacture to exacting curvatures and are more
    >>>easily corrected for aberrations than larger glass used for DSLRs

    >>
    >>Uh, yeah. That's why scale models are always *so* much more highly
    >>detailed than the full-size originals. :/

    >
    >Come back again after you've hand-ground and polished a diffraction-limited 16"
    >diameter mirror for a telescope and a diffraction-limited 6" diameter one.


    Vastly easier than doing the same for a lens that's 1.5mm in diameter.

    --
    Ray Fischer
     
    Ray Fischer, Nov 25, 2008
    #3
  4. Ray Fischer

    Chris H Guest

    In message <>, Dale Tems
    <> writes
    >On Tue, 25 Nov 2008 12:42:47 +0000 (UTC), Stuffed Crust
    ><> wrote:
    >
    >>In rec.photo.digital.slr-systems Stephen Bishop <> wrote:
    >>> But I will observe that he seems to be a perfect example of someone,
    >>> who in the timeless words of Jerry Clower, is educated beyond his
    >>> intelligence.

    >>
    >>... gah, tell me about it. It wasn't even remotely worth trying to
    >>re-demonstrate the fundamental fallacy in that drivel.
    >>
    >> - Solomon

    >
    >
    >Dear Resident-Troll,
    >
    > Your reply is completely off-topic. Here are some topics that befit this
    >newsgroup. Please consider them for future discussions and posts:
    >1. P&S cameras


    If P&S are that good why don't the places that have the technology to
    tell the difference not use them?

    You would have thought that people doing satellites and spy planes would
    be using P&S technology. Likewise the surveillance teams for the
    security services and armed forces. Yet they all use DSLR technology.

    Incidentally the BBC (for their news teams) looked at using
    camera-phones and P&S and decided they weren't good enough.

    It is strange that despite it being "obvious" that P&S are better all
    those with the ability to test this claim spend more money on DSLRs and
    use them... Is EVERYONE that stupid?


    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 25, 2008
    #4
  5. Ray Fischer

    Chris H Guest

    In message <>, Craig-Bolts
    <> writes
    >On Tue, 25 Nov 2008 13:26:30 +0000, Chris H <> wrote:
    >
    >>In message <>, Dale Tems
    >><> writes
    >>>On Tue, 25 Nov 2008 12:42:47 +0000 (UTC), Stuffed Crust
    >>><> wrote:
    >>>
    >>>>In rec.photo.digital.slr-systems Stephen Bishop
    >>>><> wrote:
    >>>>> But I will observe that he seems to be a perfect example of someone,
    >>>>> who in the timeless words of Jerry Clower, is educated beyond his
    >>>>> intelligence.
    >>>>
    >>>>... gah, tell me about it. It wasn't even remotely worth trying to
    >>>>re-demonstrate the fundamental fallacy in that drivel.
    >>>>
    >>>> - Solomon
    >>>
    >>>
    >>>Dear Resident-Troll,
    >>>
    >>> Your reply is completely off-topic. Here are some topics that befit this
    >>>newsgroup. Please consider them for future discussions and posts:
    >>>1. P&S cameras

    >>
    >>If P&S are that good why don't the places that have the technology to
    >>tell the difference not use them?
    >>
    >>You would have thought that people doing satellites and spy planes would
    >>be using P&S technology. Likewise the surveillance teams for the
    >>security services and armed forces. Yet they all use DSLR technology.

    >
    >Uh huh, SUUUURRE they do. They use DSLRs in spy-planes and satellites.
    >I bet you
    >run around the rings of Saturn in your Nike sneakers too.


    Actually NASA uses Nikon DSLRs both in the ground and in space. Also
    they use DSLR technology in UVA's I know I worth with one of the
    companies doing it.

    >Security services? Armed forces? Oh, I got you there, read below. I'm glad you
    >mentioned that. Your thinking that any of those people would use DSLRs makes
    >your statement as oxymoronic as it gets. You didn't quite think things through
    >before posting your troll, did you.


    Yes. Both the US and UK Security Forces and use DSLRs for surveillance
    work.

    >>Incidentally the BBC (for their news teams) looked at using
    >>camera-phones and P&S and decided they weren't good enough.
    >>
    >>It is strange that despite it being "obvious" that P&S are better all
    >>those with the ability to test this claim spend more money on DSLRs and
    >>use them... Is EVERYONE that stupid?

    >
    >Pretty much! Never underestimate the stupidity of humanity.

    Well you are showing that to be accurate.
    The BBC have more than a passing idea of what they are doing.

    So far al you have been doing is repeating rubbish with nothing to back
    it up. Not even the easy step of posting pictures to prove it.


    >Maybe if they knew how to shop for cameras and what to look for in them they
    >would realize the advantages of P&S cameras.


    P&S do have advantages. I have one.

    >Isn't it odd though, in some news items from the Iraq war I spied quite
    >a few of
    >the armed security personnel carrying one of my more favorite P&S cameras that
    >has a titanium shell, snuggly strapped around their neck and shoulder and
    >hanging alongside their ammunition belts.


    Why do you think they call then Grunts? If you saw them they were not
    doing surveillance. In their situation I would use a P&S as it is small
    and easy to use in one hand. Also it is cheap. It takes "passable"
    pictures.
    The average grunt would not carry a DSLR in that situation.

    Only snipers carry a sniper rifle and machine gunners a machine gun.
    This is despite the average grunt only carrying an M16.

    Your argument is similar. Because all the grunts carry P&S there is no
    need for a Machine gun or a Sniper.

    I certainly now what the Intelligence and recce teams use for
    photography and it ain't P&S....

    >They understand the value of precision
    >optics housed in durable. They also understand the value of being perfectly
    >silent when its important.


    My experience of the US military is that the Grunts understand very
    little. I doubt any know what "optics" are out side a bar. As for
    being silent.. DSLR's can be. However you will not be taking photos if
    you are that close. If you are that close it usually means you have
    made a cock up.

    If the best you can do is "I watch some news reports" It ain't worth
    shit.

    What I can tell you is that for recce WE carried DSLR's in the Middle
    East. NOT P&S But then we weren't grunts and we weren't taking snaps to
    impress the girlfriend back home.

    >Maybe you too should learn to do what your DSLR cannot do.


    I do know. I also know what my P&S can and can not do.

    >While you're learning how to remain silent when working (what your
    >camera cannot
    >do), educate yourself, make good use of that time.


    Physician heal thyself.

    You have no idea what you are talking about.


    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 25, 2008
    #5
  6. Ray Fischer

    Ray Fischer Guest

    Collin Barger <> wrote:
    >On 25 Nov 2008 06:12:37 GMT, (Ray Fischer) wrote:
    >
    >>ChaseOslo <coslo@.org> wrote:
    >>> John A.

    >>
    >>>>>Smaller lenses are easier to manufacture to exacting curvatures and are more
    >>>>>easily corrected for aberrations than larger glass used for DSLRs
    >>>>
    >>>>Uh, yeah. That's why scale models are always *so* much more highly
    >>>>detailed than the full-size originals. :/
    >>>
    >>>Come back again after you've hand-ground and polished a diffraction-limited 16"
    >>>diameter mirror for a telescope and a diffraction-limited 6" diameter one.

    >>
    >>Vastly easier than doing the same for a lens that's 1.5mm in diameter.

    >
    >Not necessarily so,


    Yes, "necesssarily" so.

    > there are "tricks" to grinding some smaller lenses. In fact,
    >one of Leeuwenhoek's tricks to "grinding" single objective lenses that can
    >magnify up to ~100x was to simply draw a long thread of glass. Heating that
    >thread's end in a flame until it melted into a small ball on the end of the
    >thread, then feeding the rest of that thread into the molten miniature ball of
    >glass held at the edge of a flame. As the ball grew larger it would take on a
    >perfect spherical shape due to the cohesion properties of glass molecules. No
    >different than how a drop of water will form a perfect sphere in a weightless
    >atmosphere when allowed to come to rest.


    Which is hardly a "diffraction-limited" lens, is it?

    [...]
    >There are other opticians tricks for smaller lenses. But I'm not privy to most
    >of those methods. I just know they exist. There seems to be a cost-effective
    >"sweet spot" to grinding curvatures in glass. Too large and it becomes extremely
    >difficult to obtain and attain a perfect figure. Too small and it becomes
    >equally difficult. This could be why the P&S camera fares so well commercially,
    >to get excellent camera AND excellent diffraction-limited lenses for such a low
    >cost, most of the optical components are well within that "sweet-spot" size.


    Except that they're obviously not "excellent diffraction-limited
    lenses". P&S cameras sell well because they're cheap and convenient.

    --
    Ray Fischer
     
    Ray Fischer, Nov 25, 2008
    #6
  7. Ray Fischer

    Chris H Guest

    In message <>, PlacerJohan
    <> writes
    >>I certainly now what the Intelligence and recce teams use for
    >>photography and it ain't P&S....

    >
    >Oh yes, you're so intelligent that you'll be using a camera for surveillance in
    >war conditions where the noise from your camera will get you killed. You are SO
    >intelligent.


    I am. I HAVE used an SLR for surveillance work in a war zone. Any your
    experience is?

    >>What I can tell you is that for recce WE carried DSLR's in the Middle
    >>East. NOT P&S But then we weren't grunts and we weren't taking snaps to
    >>impress the girlfriend back home.

    >
    >No, your commanders were trying to get rid of you by alerting anyone to your
    >position as you shot photos.


    Hadly. It is clear you have never used an SLR out doors let alone in a
    war zone.

    Incidentally the ONLY people to shoot at us were the US "friendly"
    forces and we weren't taking pictures at the time,

    >>>Maybe you too should learn to do what your DSLR cannot do.

    >>I do know. I also know what my P&S can and can not do.

    >Apparently not enough. You weren't even bright enough to realize someone was
    >trying to get you killed. This may eventually work to everyone's advantage.
    >Darwinism to the rescue.


    Quite. Dawinisum. We got in. took the pictures and got out.
    Survival of the fittest.

    You on the other hand have only ever seen warfare on the TV

    >>You have no idea what you are talking about.

    >
    >Quite the contrary. You don't even have any idea of what's happening
    >around you.


    Well I have the photos to prove it. Which is more than you do


    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 25, 2008
    #7
  8. In rec.photo.digital.slr-systems Collin Barger <> wrote:
    > On 25 Nov 2008 06:12:37 GMT, (Ray Fischer) wrote:


    >>ChaseOslo <coslo@.org> wrote:
    >>> John A.

    >>
    >>>>>Smaller lenses are easier to manufacture to exacting curvatures and are more
    >>>>>easily corrected for aberrations than larger glass used for DSLRs
    >>>>
    >>>>Uh, yeah. That's why scale models are always *so* much more highly
    >>>>detailed than the full-size originals. :/
    >>>
    >>>Come back again after you've hand-ground and polished a diffraction-limited 16"
    >>>diameter mirror for a telescope and a diffraction-limited 6" diameter one.

    >>
    >>Vastly easier than doing the same for a lens that's 1.5mm in diameter.


    > Not necessarily so, there are "tricks" to grinding some smaller lenses. In fact,
    > one of Leeuwenhoek's tricks to "grinding" single objective lenses that can
    > magnify up to ~100x was to simply draw a long thread of glass. Heating that
    > thread's end in a flame until it melted into a small ball on the end of the
    > thread, then feeding the rest of that thread into the molten miniature ball of
    > glass held at the edge of a flame. As the ball grew larger it would take on a
    > perfect spherical shape due to the cohesion properties of glass molecules. No
    > different than how a drop of water will form a perfect sphere in a weightless
    > atmosphere when allowed to come to rest. The glass having stronger bonds will
    > fight the pull of gravity easier and can be made larger without any distortion
    > here on earth. Using the molecular properties of glass itself to form a perfect
    > lens.


    > When as a child and I needed a quick pocket microscope for a trip into the
    > swamps, meadows, and woods, I would sometimes make one of these and mount the
    > lens in a same-sized hole in a piece of thin cardboard. You'd be surprised at
    > the optical power and visual clarity you can obtain through a lens made in this
    > manner. It takes practice, a very steady hand, keeping the forming glass ball at
    > just the proper melt-temperature and many trials and error to know how large of
    > a lens you can make this way. As well as different glasses have different
    > degrees of viscosity to them when melted. Some glasses would hold in a perfect
    > sphere up to 3-4mm in dia. according to memory of childhood experiments. That's
    > quite a bit of aperture to peer through when held up to the eye. I also recall,
    > that by my rough way-back-when estimates against some of my "store bought"
    > microscopes (in parens because I always modified them and made them better)
    > these single-lens microscopes made from a thread of melted glass would average
    > anywhere from 80x to 120x magnification when compared to known subjects and
    > known magnifications. The caveat being the smaller (<2mm dia.) more perfect
    > sphere was the higher power but required intense light to make it useful.
    > Backlit sunlight was handy in the meadow, that's why it works so well for a
    > simple, inexpensive, impromptu pocket-microscope. Needing nothing more than a
    > bit of lab glass-tubing to draw into a thread, an alcohol lamp, a piece of
    > cardboard, and a bit of tape to hold the stem of the spherical-lens to the
    > cardboard (the spherical lens inserted into a hole in the cardboard, just like
    > Leeuwenhoek's metal plate would hold one).


    > Some of Leeuwenhoek's more powerful single-lens microscopes were made in a
    > different manner, but I've not heard of anyone learning what method he used to
    > grind and polish those lenses. It might have been a different method of melting
    > them into perfect spheres or he used small diameter tubes to grind them to
    > perfect shapes. When a ball of glass is held to a tube's end that is spun with
    > diamond powder on it, and then ball of glass is rotated against that spinning
    > tube's end, you get perfectly spherical glass form. This is also how decorative
    > and spiritualist's crystal-balls are made in large sizes.


    > There are other opticians tricks for smaller lenses. But I'm not privy to most
    > of those methods. I just know they exist. There seems to be a cost-effective
    > "sweet spot" to grinding curvatures in glass. Too large and it becomes extremely
    > difficult to obtain and attain a perfect figure. Too small and it becomes
    > equally difficult. This could be why the P&S camera fares so well commercially,
    > to get excellent camera AND excellent diffraction-limited lenses for such a low
    > cost, most of the optical components are well within that "sweet-spot" size.


    A similar method I used as a boy was waterdrop lenses. The same forces
    of surface tension make a small drop of water into an approximate
    sphere. The question is how to hold it without distorting the lens
    shape of the ends too much. The answer was to drive a gramophone
    needle, a fat smoothly tapered highly polished steel needle, just a
    little through a copper coin, leaving a hole on one side, a smaller
    one on the other, and a beautifully smooth and curved cone between
    them. Anyone remember that clever trick? It involved a sawn-off wine
    bottle cork.

    You then dropped your water drip into the smooth polished conical hole
    thus formed. That formed the objective lens of a microscope, and a
    conventional multi-element high power magnifier formed the eyepiece.
    In a cold humid atmosphere you could get five to ten minutes of good
    microscopy from it before evaporation went far enough to spoil the
    optical geometry.

    --
    Chris Malcolm
     
    Chris Malcolm, Nov 25, 2008
    #8
  9. Ray Fischer

    Chris H Guest

    In message <gghap8$2i2$>, Stuffed Crust
    <> writes
    >In rec.photo.digital.slr-systems PlacerJohan <> wrote:
    >> Certainly not from within any distance where they can be heard from a
    >> block away snapping off pictures.

    >
    >...or you can use a P&S and be heard two blocks off by the whine of the
    >focus and zoom motors. Whatever.


    Especially at night. This is why you use manual focus if noise is THAT
    much of a problem

    If noise IS a problem the mirror is not a problem on a DSLR as you can
    get around that. However it is VERY unusual if you are that close and it
    is that quite... in my personal experience in the field not watching the
    TV .

    >> You must be a pretty poor shopper if you don't realize the many more
    >> advantages over a DSLR.

    >
    >A (compact) P&S camera has exactly one undisputable advantage over a
    >DSLR -- size/weight.


    Yes. Very useful for work where you are doing very close surveillance
    in a confined apace. That said there are other much better covert
    cameras about.

    > But then a tiny P&S camera has very few of the
    >"25" advantages you so thoughtfully regurgitate so often. Indeed, is
    >there any one camera out there that hits all, or even 2/3rds of that
    >list?


    None. More to the point he can't list any.

    >
    >> Oh yes, you're so intelligent that you'll be using a camera for
    >> surveillance in war conditions where the noise from your camera will
    >> get you killed. You are SO intelligent.

    >
    >It's more intelligent to conduct surveillence at the greatest
    >distance possible.


    So true. In fact from the sort of places a P&S can not give you a decent
    picture of the target.

    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 25, 2008
    #9
  10. Ray Fischer

    Chris H Guest

    In message <>, Howie Coldan
    <> writes
    >On Tue, 25 Nov 2008 22:27:09 +0000, Chris H <> wrote:
    >
    >>In message <gghap8$2i2$>, Stuffed Crust
    >><> writes
    >>>In rec.photo.digital.slr-systems PlacerJohan <> wrote:
    >>>> Certainly not from within any distance where they can be heard from a
    >>>> block away snapping off pictures.
    >>>
    >>>...or you can use a P&S and be heard two blocks off by the whine of the
    >>>focus and zoom motors. Whatever.

    >>
    >>Especially at night. This is why you use manual focus if noise is THAT
    >>much of a problem
    >>
    >>If noise IS a problem the mirror is not a problem on a DSLR as you can
    >>get around that. However it is VERY unusual if you are that close and it
    >>is that quite... in my personal experience in the field not watching the
    >>TV .

    >
    >Thanks. You've just outted yourself as just another pretend-photographer troll.
    >
    >First of all any decent P&S camera is totally silent when focusing. Better ones
    >are also totally silent when zooming.
    >
    >"Especially at night"? LOL! You can't even see through that OVF at night to
    >frame and focus.


    I think that ends the conversation. You don't know what you are talking
    about.


    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 26, 2008
    #10
  11. Ray Fischer

    Chris H Guest

    In message <>, steve-d
    <> writes
    >On Tue, 25 Nov 2008 22:22:07 +0000, Chris H <> wrote:
    >
    >>In message <>, PlacerJohan
    >><> writes
    >>>>I certainly now what the Intelligence and recce teams use for
    >>>>photography and it ain't P&S....
    >>>
    >>>Oh yes, you're so intelligent that you'll be using a camera for
    >>>surveillance in
    >>>war conditions where the noise from your camera will get you killed.
    >>>You are SO
    >>>intelligent.

    >>
    >>I am. I HAVE used an SLR for surveillance work in a war zone. Any your
    >>experience is?

    >
    >I note you say SLR. That says much.


    It was prior to DSLRs
    Kurdistan in 1988.

    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 26, 2008
    #11
  12. Ray Fischer

    Chris H Guest

    In message <>, Howie Coldan
    <> writes
    >On Tue, 25 Nov 2008 22:27:09 +0000, Chris H <> wrote:
    >
    >>In message <gghap8$2i2$>, Stuffed Crust
    >><> writes
    >>>In rec.photo.digital.slr-systems PlacerJohan <> wrote:
    >>>> Certainly not from within any distance where they can be heard from a
    >>>> block away snapping off pictures.
    >>>
    >>>...or you can use a P&S and be heard two blocks off by the whine of the
    >>>focus and zoom motors. Whatever.

    >>
    >>Especially at night. This is why you use manual focus if noise is THAT
    >>much of a problem
    >>
    >>If noise IS a problem the mirror is not a problem on a DSLR as you can
    >>get around that. However it is VERY unusual if you are that close and it
    >>is that quite... in my personal experience in the field not watching the
    >>TV .

    >
    >Thanks. You've just outted yourself as just another pretend-photographer troll.
    >
    >First of all any decent P&S camera is totally silent when focusing. Better ones
    >are also totally silent when zooming.
    >
    >"Especially at night"? LOL! You can't even see through that OVF at night to
    >frame and focus. A P&S camera has you beat 100x's over in this regard. This
    >comment of yours alone proves you are a pretend-photographer troll.


    A P&S LOOSES 1200% in this situation.
    Unlike the DSLR shutter noise which does not carry very far the P&S has
    an illuminated screen for framing the picture. This illuminates the
    users face well enough for anyone on a 200 Metre semicircle in front of
    the photographer to see them and shoot them.

    You have clearly never done any surveillance photography.

    >Why do you
    >think I saw all those P&S cameras around the necks of the military
    >security?


    Because they were NOT photographers. The Military use DSLRs for
    surveillance the JSP trains on (and uses) DSLR's and not P&S except for
    a few specific uses.

    The people you see with the P&S are either taking snaps to impress the
    girlfriend or carrying the P&S because it is small, light, fully
    automatic, virtually idiot proof and cheap. NOT because of it's picture
    quality.

    The difference between you and me is I HAVE worked with military
    photographers and been in the field.

    It is clear you do not know what you are talking about.

    --
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris H, Nov 26, 2008
    #12
  13. Collin Barger <> writes:

    >Thinking about it now, and knowing what I do about gemstone facet grinding
    >(lapidary, another hobby), it wouldn't be too far-fetched to imagine them using
    >a similar lapping device and rigging up a small plate of glass to the end of an
    >adjustable-radius arm that spun on its own axis. A perfect dialed-in diopter in
    >the glass could be formed and polished this way in short time. The final figure
    >applied by different densities of firm but flexible lapping mats that would
    >carry-over the exact final figuring needed, only determined by how much measured
    >pressure was applied. That would be my best guess on how it is done. I've really
    >not pondered on this much until now, while typing this. (Don't ask me about
    >concave surfaces, I've used up my pondering time for this post.) The cost
    >savings being in the short amount of time it would require to bring such a small
    >lens to a perfect curve and smoothness. The converse being true on large glass
    >lens shapes. No cost-savings in grinding, polishing, figuring, and testing time.
    >The expenses of larger glass lenses (which includes mirrored ones) polished to
    >diffraction-limits eaten up in labor-time done by expert craftsmen in the field.


    That's interesting, but you haven't addressed the scaling effects. A
    P&S camera may have a sensor whose dimensions are 1/5 as large as a
    "full frame" DSLR or even smaller. To get the same field of view, it
    uses a lens of 1/5 the focal length. To provide the same image quality,
    the size of the aberrations in the image plane needs to be 1/5 as large
    (since the small-sensor image is enlarged a factor of 5X more to give
    the same size print or screen image).

    Now, if you take a lens design suitable for a particular field of view
    on a "full frame" camera and simply scale all the dimensions (surface
    radii, spacings, etc) by a factor of 1/5, you get a lens of 1/5 the
    focal length that's suitable for use on the P&S camera, covering the
    same FOV. The aberrations automatically scale down, so the aberrations
    are 1/5 as large on the sensor - and the same size on the print. The
    smaller lens elements are certainly lighter, and may be cheaper to
    fabricate. But the tolerances on element spacing and centration are now
    5 times tighter - which will cost more, eating some of those savings.

    And diffraction blur does *not* scale down like the aberrations do. If
    you keep the f/number the same during the focal length shrink, the
    diffration blur remains the same absolute size - which is 5X larger
    relative to the image dimensions on the small sensor, and 5X as bad when
    enlarged.

    You can see this same effect in microscope objectives. To get higher
    power, the focal length of the objective becomes smaller. But all but
    the lowest-power objectives are limited by diffraction, and simply
    reducing focal length to increase magnification does not improve the
    ability to resolve detail. Higher magnification objectives must have a
    higher NA (equivalent to lower f/number) to resolve more detail.

    Dave
     
    Dave Martindale, Nov 27, 2008
    #13
  14. Ray Fischer

    Steve Guest

    On Thu, 27 Nov 2008 02:36:55 -0600, Collin Barger
    <> wrote:

    >On Thu, 27 Nov 2008 06:39:01 +0000 (UTC), (Dave Martindale)
    >wrote:
    >
    >>
    >>And diffraction blur does *not* scale down like the aberrations do. If
    >>you keep the f/number the same during the focal length shrink, the
    >>diffration blur remains the same absolute size - which is 5X larger
    >>relative to the image dimensions on the small sensor, and 5X as bad when
    >>enlarged.

    >
    >Exactly, but P&S lenses are ground to diffraction-limited tolerances, they have
    >to be for those smaller photo-sites on their smaller sensors. This is about the
    >only complaint people have on the better-quality P&S cameras, not CA nor
    >softness of details nor anything else. Just that diffraction robs them of good
    >contrasting edges at smaller apertures. DSLR lenses are not diffraction-limited.
    >They don't have to be due to the larger photo-sites that will never resolve that
    >kind of angular distance. That's the whole point.


    I hate to tell you this but people complain all the time about P&S
    lenses and their CA and softness of detail. The best ones are not so
    great and the worst ones are abysmal.

    Steve
     
    Steve, Nov 27, 2008
    #14
  15. Ray Fischer

    Ray Fischer Guest

    Collin Barger <> wrote:
    >On Thu, 27 Nov 2008 06:39:01 +0000 (UTC), (Dave Martindale)
    >wrote:
    >
    >>
    >>And diffraction blur does *not* scale down like the aberrations do. If
    >>you keep the f/number the same during the focal length shrink, the
    >>diffration blur remains the same absolute size - which is 5X larger
    >>relative to the image dimensions on the small sensor, and 5X as bad when
    >>enlarged.

    >
    >Exactly, but P&S lenses are ground to diffraction-limited tolerances,


    They most certainly are not.

    --
    Ray Fischer
     
    Ray Fischer, Nov 27, 2008
    #15
  16. Ray Fischer

    Ray Fischer Guest

    Collin Barger <> wrote:
    >
    >** poor choice of words corrected**
    >
    >On Thu, 27 Nov 2008 06:39:01 +0000 (UTC), (Dave Martindale)
    >wrote:
    >
    >>
    >>And diffraction blur does *not* scale down like the aberrations do. If
    >>you keep the f/number the same during the focal length shrink, the
    >>diffration blur remains the same absolute size - which is 5X larger
    >>relative to the image dimensions on the small sensor, and 5X as bad when
    >>enlarged.

    >
    >Exactly, but P&S lenses are ground to diffraction-limited tolerances,


    They are not.

    --
    Ray Fischer
     
    Ray Fischer, Nov 27, 2008
    #16
  17. Ray Fischer

    Ray Fischer Guest

    Curt R <> wrote:
    > (Ray Fischer) wrote:
    >>Collin Barger <> wrote:
    >>> (Dave Martindale)


    >>>>And diffraction blur does *not* scale down like the aberrations do. If
    >>>>you keep the f/number the same during the focal length shrink, the
    >>>>diffration blur remains the same absolute size - which is 5X larger
    >>>>relative to the image dimensions on the small sensor, and 5X as bad when
    >>>>enlarged.
    >>>
    >>>Exactly, but P&S lenses are ground to diffraction-limited tolerances,

    >>
    >>They most certainly are not.

    >
    >Uh huh, sure, ... that's why they only show signs of minor image softness when
    >smallest apertures are used.


    No, it's because already-poor lenses and sensors don't degrade much
    more because of diffraction.

    > The tell-tale sign of optics that are
    >diffraction-limited.


    No, it isn't. It's a sign that the effects of diffraction are
    overwhelmed by the much-greater flaws elsewhere in the system.

    High-quality lenses are expensive. If you tell me that expensive
    lenses are being used in cheap cameras then I'm going to tell you
    that you're stupid.

    --
    Ray Fischer
     
    Ray Fischer, Nov 27, 2008
    #17
  18. Ray Fischer

    Ray Fischer Guest

    P.Garnet <> wrote:
    > (Ray Fischer) wrote:
    >>Curt R <> wrote:
    >>> (Ray Fischer) wrote:
    >>>>Collin Barger <> wrote:
    >>>>> (Dave Martindale)

    >>
    >>>>>>And diffraction blur does *not* scale down like the aberrations do. If
    >>>>>>you keep the f/number the same during the focal length shrink, the
    >>>>>>diffration blur remains the same absolute size - which is 5X larger
    >>>>>>relative to the image dimensions on the small sensor, and 5X as bad when
    >>>>>>enlarged.
    >>>>>
    >>>>>Exactly, but P&S lenses are ground to diffraction-limited tolerances,
    >>>>
    >>>>They most certainly are not.
    >>>
    >>>Uh huh, sure, ... that's why they only show signs of minor image softness when
    >>>smallest apertures are used.

    >>
    >>No, it's because already-poor lenses and sensors don't degrade much
    >>more because of diffraction.
    >>
    >>> The tell-tale sign of optics that are
    >>>diffraction-limited.

    >>
    >>No, it isn't. It's a sign that the effects of diffraction are
    >>overwhelmed by the much-greater flaws elsewhere in the system.
    >>
    >>High-quality lenses are expensive. If you tell me that expensive
    >>lenses are being used in cheap cameras then I'm going to tell you
    >>that you're stupid.

    >
    >You haven't a clue.


    Do YOU think that expensive lenses are put into cheap cameras?

    > You do realize that I hope. You will someday, if you ever


    Spare us the bullshit, idiot. You obviously don't have any
    intelligent response.

    --
    Ray Fischer
     
    Ray Fischer, Nov 27, 2008
    #18
  19. Ray Fischer wrote:
    > P.Garnet <> wrote:


    >
    > Do YOU think that expensive lenses are put into cheap cameras?
    >
    >> You do realize that I hope. You will someday, if you ever

    >
    > Spare us the bullshit, idiot. You obviously don't have any
    > intelligent response.


    Say, aren't you the same guy who posts ascii signs admonishing others to
    not feed the troll?

    --
    lsmft
     
    John McWilliams, Nov 28, 2008
    #19
  20. Ray Fischer

    Ray Fischer Guest

    stephen clangston <> wrote:
    > (Ray Fischer) wrote:
    >>P.Garnet <> wrote:
    >>> (Ray Fischer) wrote:
    >>>>Curt R <> wrote:
    >>>>> (Ray Fischer) wrote:
    >>>>>>Collin Barger <> wrote:
    >>>>>>> (Dave Martindale)
    >>>>
    >>>>>>>>And diffraction blur does *not* scale down like the aberrations do. If
    >>>>>>>>you keep the f/number the same during the focal length shrink, the
    >>>>>>>>diffration blur remains the same absolute size - which is 5X larger
    >>>>>>>>relative to the image dimensions on the small sensor, and 5X as bad when
    >>>>>>>>enlarged.
    >>>>>>>
    >>>>>>>Exactly, but P&S lenses are ground to diffraction-limited tolerances,
    >>>>>>
    >>>>>>They most certainly are not.
    >>>>>
    >>>>>Uh huh, sure, ... that's why they only show signs of minor image softness when
    >>>>>smallest apertures are used.
    >>>>
    >>>>No, it's because already-poor lenses and sensors don't degrade much
    >>>>more because of diffraction.
    >>>>
    >>>>> The tell-tale sign of optics that are
    >>>>>diffraction-limited.
    >>>>
    >>>>No, it isn't. It's a sign that the effects of diffraction are
    >>>>overwhelmed by the much-greater flaws elsewhere in the system.
    >>>>
    >>>>High-quality lenses are expensive. If you tell me that expensive
    >>>>lenses are being used in cheap cameras then I'm going to tell you
    >>>>that you're stupid.
    >>>
    >>>You haven't a clue.

    >>
    >>Do YOU think that expensive lenses are put into cheap cameras?
    >>
    >>> You do realize that I hope. You will someday, if you ever

    >>
    >>Spare us the bullshit, idiot. You obviously don't have any
    >>intelligent response.

    >
    >Let's see if you can follow this simple grade-school level logic:


    You're not smart enough to be condescending, asshole.

    >Smaller lenses are in P&S cameras.
    >
    >P&S cameras have diffraction-limited quality.


    Bullshit.

    --
    Ray Fischer
     
    Ray Fischer, Nov 28, 2008
    #20
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