The continuing saga of my Sony A100

Discussion in 'Sony' started by BobF, Aug 5, 2006.

  1. BobF

    BobF Guest

    Spent the last little while taking pictures of my garden and viewing them on the
    computer, modifying them, and running out again... I'm using a Samsung LCD.

    One pet peeve I've always had with digital cameras was their inability to shoot
    bright yellow and white flowers in sunlight. The first cam I had was so bad you
    wouldn't have known it was a flower... Cameras did get better over the years,
    the best results so far I've seen were with my D70. This Sony is also fairly
    good, but... in some cases, very bad.

    A few close ups I took were ok, but if the flower (or yellow bean in one case)
    is only a small part of the picture, it is blasted out! In some ways the
    pictures remind me of movie camera color - kind of like Ektachrome in bad
    developer or something... closer to a P&S then a DSLR... Too much contrast and
    poor linearity...

    Wide shots of the garden appear to be too light. After adjusting -1 stop, they
    appear bizarre... the camera can't handle the entire range of light, and makes
    the average a bit too high. It needs a different mid bias.

    I managed to correct some of the shots with a negative gamma curve applied by
    hand in Micrografx. This camera is going to need curves !!

    Taking the picture into Elements 4 and hitting 'auto color correct' made a
    change right away. Does that mean something?

    (I would LOVE to see similar shots from the Nikon D200 which has the same
    sensor. Anyone know of a Pbase page of D200 garden shots?)

    The auto WB gives weird results, some shade shots are a weird green - I mean the
    bark as well as the leaves... if however I pick 'shade' in the menu it does a
    better job.

    I didn't like the choice of ISO in auto, so I think I'll keep it manual. That's
    my habit anyway. It picked 125 in a shade area and then went to 1/30 sec!
    weird...

    So far I've been in multi-segment meter and fixed-middle-spot focus. ISO is now
    locked at 400. Will try different color modes, also the DR on and off. The
    default for that is 'middle' sort of... See the review at that digital cam
    review place.

    If anyone is interested, I can upload shots to my Pbase pages. I won't if there
    is no interest.

    I wish I had my Nikon to compare!

    Bob
     
    BobF, Aug 5, 2006
    #1
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  2. BobF

    ian Guest

    dpreview complained about the multisegment metering doing something similar.
    Small areas of very bright light did cause an underexposure.
    Turn the DRO onto advanced and report back.
    Auto white balance isn't too great on canon either. Specific white balance
    parameters are good. The manual or custom functions are good. RAW and
    adjustment with the canon software is spot on for me so try that out too
    with the sony stuff.
     
    ian, Aug 5, 2006
    #2
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  3. BobF

    bmoag Guest

    "the camera can't handle the entire range of light"

    You have it exactly.
    Current digital sensors, regardless of how many pixels, have a dynamic range
    that may be no better than .1fstop (according to Seikonic in their
    advertising materials) and for all practical purposes is clearly less than
    even transparency film.
    Digital sensors have much less latitude for overxposure than underexposure
    and the D70 is engineered to underexpose because as we all know you can
    bring up detail from shadows but can do nothing with blown out highlights.
    As such the megapixel race, just like the CPU speed race, is beside the
    point even at this early time in the development of digital photography.
    What is really needed is a digital sensor with significantly increased
    exposure latitude or an in-camera software method of varying the sensitivity
    of the sensors during exposure to tame the highlights.
     
    bmoag, Aug 5, 2006
    #3
  4. BobF

    BobF Guest

    Thats what the Fujifilm camera does... it has extra 'pixels' for the over-white
    and adds them in later.
     
    BobF, Aug 6, 2006
    #4
  5. BobF

    BobF Guest

    I tried both ways, but I should try the 2 special zone modes as well.
     
    BobF, Aug 6, 2006
    #5
  6. There's a reason for this. Applies to many DSLRs. The focusing screens -
    like the latest one on the D200 - are made almost transparent to ensure
    a bright viewing image from the small screen area. The meter cells are
    in the prism. Under certain conditions, a light source can 'shine
    through' to one meter cell.

    The solution on the KM 7D was to have the screen changed for a Type M or
    ML, which reduces the screen brightness by over a stop, and makes it
    very hard to view with low aperture, short focal length lenses. The
    metering would be adjusted overall to compensate. The brightness
    remained acceptable with lenses faster than f4, especially long lenses.
    As a bonus, depth of field preview actually works with the M or ML
    screen; although a preview button is provided on the A100, it is
    meaningless, as the result is not an accurate preview. When you fit a
    50mm f1.4 lens, the d-o-f you see is equivalent to a 50mm f4 even when
    at full aperture, as the exit pupil of the lens is reduced by the
    semi-transparent focusing screen and eyepiece/condensor effect
    combination. These bright screens also make manual focusing impossible,
    as a brief play around with the dioptre control will show you. The AF
    markings are, also, separated from the focus screen surface by one or
    more shims, inserted in the factory to collimate the lens
    mount/screen/mirror setup. When the AF markings are dead sharp by
    adjusting the dioptre, you are not focusing the eyepiece on the screen
    surface, and all your manual focusing will be slightly out.

    The solution is to set a lens at infinity (pick one which checks out on
    a good film camera body to actually focus on infinity, when set there -
    not one which focuses beyond). If you can, do a check on a focus screen
    inserted on the film gate of a camera, to establish the correct setting
    for infinity. Looking through the DSLR, with the lens set to this
    reference and pointed at an infinity subject (greater than 300 feet)
    adjust the eyepiece dioptre until the image (not the AF markings) is as
    sharp as possible. Now adjust the dioptre control until the AF markings
    are maximum sharpness. Make a note of the difference - i.e., one click
    anti-clockwise or whatever it may be. For accurate manual focus in
    future, just focus on the AF sensor markings, then adjust the setting by
    this amount.

    Metering is completely screwed up by the 'Haoda' matt screens with
    central micro/split focusing aid. Not only does the screen density
    change overall metering, any light source hitting the central focusing
    aid may produce an extreme underexposure.

    Sony so far has not announced any alternative screens for the A100.

    David
     
    David Kilpatrick, Aug 6, 2006
    #6
  7. 1/10 of a stop dynamic range? Which camera would that be?
    Must be a very special application. Scanning of b/W art?
    Hmmm ... what are they selling?
    Can you explain
    http://www.clarkvision.com/imagedetail/dynamicrange2/
    then?
    Just like slide film, only a bit more so.
    So you are saying that we need better digital than we ever
    had film?

    -Wolfgang
     
    Wolfgang Weisselberg, Aug 11, 2006
    #7
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