Interesting Leica product announcements today ...

Discussion in 'Digital Photography' started by Bruce, May 10, 2012.

  1. Bullshit. Wolfgang is opinionated and scrappy certainly, but quite
    knowledgable. And, to your point, beats me up when I'm imprecise, but
    NOT when say nice things about my Nikon gear. Your suggestion that he's
    a Canon-specific fan-boi is clearly false.
     
    David Dyer-Bennet, May 19, 2012
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  2. Precisely the circumstance in which I was suggesting it was a useful
    thing to do.
     
    Chris Malcolm, May 19, 2012
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  3. This particular kind of noise reduction (subtraction of an
    equivalently exposed black image) seems to me on theoretical grounds
    to be more likely to improve image quality than reduce it. It's
    completely different from the kind of noise reduction processing used
    in translating RAW images to jpegs in camera or RAW image processor,
    which effects a compromise between noise reduction and detail loss.

    Looking at the results in practice, same tripod photograph with it
    switched on and off, it seems to me quite definitely to improve IQ,
    even to a determinedly pixel-peeping scrutiny.
     
    Chris Malcolm, May 19, 2012
  4. Bruce

    John A. Guest

    The idea is that any non-random noise sources will negate each other
    in the two exposures, while random noise will tend to average out as
    well.

    A similar approach would be to take two or more exposures and average
    the pixels together, provided you can get the registration right. In
    theory, the average of a number of exposures approaching infinity
    should be spot-on with zero random noise. How many it would take to
    get the expected noise below the color-depth-imposed threshold would
    vary with how much noise you're dealing with I would imagine. Though
    of course there can always be outliers.

    I recall many years ago my dad had a box he could plug his video
    camera into that did that with video frames to produce a still that
    was of much better quality than and of the constituent frames.
     
    John A., May 19, 2012
  5. Not necessarily. You can often find reference patches within the same
    image - areas which you know to be of a near constant brightness for
    example - and measure the statistics of the image there. The fact that
    noise reduction (for viewing by humans) can work so well shows that
    perceived image quality can be improved rather than degraded.

    David
     
    David J Taylor, May 20, 2012
  6. Bruce

    Noons Guest

    David Dyer-Bennet wrote,on my timestamp of 20/05/2012 5:14 AM:
    Like all the other Canon fan-boys. And any maker fan-boys.
    Nothing but groupies. Rarely any substance or recults to show what they are
    capable of. But oh-boy: do they know how to dump on others...
     
    Noons, May 20, 2012
  7. Bruce

    Noons Guest

    David Dyer-Bennet wrote,on my timestamp of 20/05/2012 5:12 AM:
    I said "similar Pan films"...
    The image characteristics and formation for the techpan look alikes is
    completely different from the traditional b&W stuff. Negative strips examined
    on the microscope are completely different: there is no "clumping" anywhere.
    Its original design purpose was as a micro-film.
    The biggest difference I see between all these high-res films and the run of the
    mill tri-x/pan-x/t-max is that the non-exposed portion of the negative comes out
    totally transparent instead of with the usual grey "fog". To the point where
    Adox CMS20 for example can be used as a b&w "slide" film with contact
    duplication: plenty of folks at APUG have tried it and love the results. Same
    for the Rolleis. It also gives the negatives a huge dynamic range that exceeds
    what my ED9000 can do almost every time. That makes it a challenge to scan a
    high dynamic range image in its entirety without losing something off the
    "ends". HDR-like scanning works to "compress" it, but it's a RPITA time-waster...


    Who doesn't? :)
    I'm very much into bracketing. With the F6/F100 and spot meter I tend to stick
    to the zone system. But with the dslrs and the Oly m4/3, bracketing is the
    order of the day. Although I must admit I'm getting it right most of the time
    first go with the Oly. Then again, I use it a lot more than the dslrs...
     
    Noons, May 20, 2012
  8. Perfect description of Noons.

    -Wolfgang
     
    Wolfgang Weisselberg, May 20, 2012
  9. [/QUOTE]
    Random noise (if observed statistically) will grow with the square
    root of measurements, as it's a random walk.
    Actually, the total noise grows (see above), but much slower than
    the total signal. Thus, the SNR goes to infinity.

    As the main noise source is photon noise, you could just expose
    longer (and thus add the inevitable read noise less often).
    Of course, after some point your pixels will overflow, but who
    really cares for such real-life limitations, when one can just
    postulate infinitely deep electron wells?

    -Wolfgang
     
    Wolfgang Weisselberg, May 21, 2012
  10. Candles & fire in general, incandescent light, "warm white"
    lamps, --- nearly all your typical indoor lighting falls under
    that heading.
    Even if you are going to make an imbalance in post-processing
    --- starting from a balanced point increases your reach and/or
    your quality.

    -Wolfgang
     
    Wolfgang Weisselberg, May 21, 2012
  11. So let's see how the tools reconstruct that:
    http://upload.wikimedia.org/wikipedia/commons/f/fb/Moire_pattern_of_bricks_small.jpg

    While we're at it, the luminance pattern shouldn't be there
    in that textile:
    http://ueberlicht.de/wordpress/wp-content/uploads/2011/10/Luminanz-Moire-Stoermuster-Stoff.jpg

    -Wolfgang
     
    Wolfgang Weisselberg, May 21, 2012
  12. Bruce

    Trevor Guest

    I've covered that here in the past, YOU may want your candle lit photo's
    etc. to look like they were shot in daylight, but I certainly don't, so no
    filtration is necessary for me.

    You mean *IF* you are going to make an imbalance in post, *not* "even if".
    Deliberately making the color balance wrong, when it is actually what you
    want to start with, is pointless.

    Trevor.
     
    Trevor, May 21, 2012
  13. That sounds like a faulty camera - or different default settings.

    In practice, it works well in the version of Paint Shop Pro which I have.

    Cheers,
    David
     
    David J Taylor, May 21, 2012
  14. Bruce

    Trevor Guest

    Actually I do usually want incandescent coloring or I don't use them. And
    try to avoid fluoro lighting too, and usually do. But funny that fluorescent
    wasn't one you mentioned anyway! However I do have a fluoro filter in my
    kit, but since fluoro's vary so much, I find it easier to adjust in post
    these days anyway. Try finding a fluoro filter that exactly matches a quad
    phospur tube for example, good luck! :)

    Trevor.
     
    Trevor, May 22, 2012
  15. You're completely missing the point. Please read more carefully,
    I am not, repeat, NOT saying your candle lit photos should look
    like daylight.

    However, with candle light your blue channel is *severely*
    underexposed when your red channel is already at capacity.
    To fix that, you need to reduce the light hitting the red pixels
    very much and the light hitting the green pixels somewhat.[1]
    I.e. you need a filter.

    Of course you are free to use the white balance tools in post to
    re-create the very red environment.

    There is no "wrongW balance. Digital isn't film.
    Proving that you didn't grasp anything at all in this thread,
    but wanted to jump on someone to prove you're better.

    -Wolfgang

    [1] Or you need to add green and blue light, e.g. with a
    flash.
     
    Wolfgang Weisselberg, May 22, 2012
  16. Bruce

    Trevor Guest

    ?????
    "Candles & fire in general, incandescent light, "warm white" lamps, ---
    nearly all your typical indoor lighting falls under that heading"

    seems to mention lighting to me, and ignores flash of course.

    Right, so how does that support your argument about using filters on camera
    being better than post again?

    Right, when flash is not an option.

    Exactly why the best you can do is in post.
    Sometimes, but only when you must use it, and can usually be made acceptable
    at least in post. And sometimes that is what you are after, my favourite is
    to add a little fill flash when necessary, but still look like incandecent
    lights if that's what I'm after.

    Fortunately I no longer use many of my huge collection of filters. People
    starting these days are lucky they no longer need to buy many IMO.

    Trevor.
     
    Trevor, May 23, 2012
  17. Bruce

    Noons Guest

    Wolfgang Weisselberg wrote,on my timestamp of 20/05/2012 9:54 PM:

    Piss off, troll. You and the others from that german university server are more
    than well known, dipshit.
     
    Noons, May 24, 2012
  18. I ought to call you mom and tell her to wash out your mouth with lots of soap.

    -Wolfgang

    PS: You still don't have a clue.
     
    Wolfgang Weisselberg, May 25, 2012
  19. If you had kept your attributions right, you'd had seen that *I*
    wrote that.
    For a good reason. Look up the original post where it
    appeared and look for the context.
    Who said that where? So far, nonbody did, although it's easily
    demonstrated for some filters like polarizers and graduated
    ND filters and ND filters.
    Even nukes don't light near and far areas evenly.

    Nope. While you can do much in post if there is only a single
    type of light source, as soon as you have different sources
    (window and artifical comes immediately to mind) you're *much*
    better off if you don't have to correct the mixed light in post,
    but gel the lightsources to one common type before you shoot.
    Yes, this isn't always feasible.

    -Wolfgang
     
    Wolfgang Weisselberg, May 25, 2012
  20. No, but that's the one easy to see without pixel peeping.

    Does that invalidate what I said in any way?

    Wrong. What matters is what the photographer wants. The
    camera is just a tool.
    And that means the photographer is not allowed to use low ISO,
    proper light and noise reduction?
    Again, that's technical limits, not "applying AA filters to
    pointilist paintings".
    At least that's your claim. You do need to provide proof, however.
    The above wasn't even in the same continent.
    And what does that have to do with pointilist paintings, where
    the effect is used on purpose for artistic reasons?

    -Wolfgang
     
    Wolfgang Weisselberg, May 27, 2012
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