CA gets worse with time?

Discussion in 'Digital Photography' started by Zed, May 10, 2007.

  1. Zed

    Zed Guest

    The chromatic aberration was never that good with my 1st digicam: an Olympus
    C4040 from the start but I'm sure it got worse after a while. My current
    PowewrShot A710IS was virtually free from it when bought but is showing
    increasing levels of it.
    It's either my fertile imagination or physical wear in the cams?!
    Zed, May 10, 2007
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  2. Zed

    John Smith Guest

    Probably the bloom is off the camera,and you're becoming more critical,
    looking for an excuse to upgrade.

    John Smith, May 10, 2007
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  3. The chromatic aberration was never that good with my 1st digicam: an
    I have no idea if this could be a cause, but over time you can get a fair
    amount of condensation and even mold on the inside surfaces of the lenses.
    Could that possibly distort light in such a way as to increase CA? What
    *would* the effect of mold be on an image (besides presumably making it a
    bit softer)?

    --Mike-- Chain Reaction Bicycles
    Mike Jacoubowsky, May 10, 2007
  4. Zed

    JohnR66 Guest

    I think it is you. It is possible for a lens to become misaligned, but you'd
    probably notice other artifacts along with CA.
    JohnR66, May 10, 2007
  5. Zed

    Wayne Guest

    Yes, I agree wholeheartedly. Ooops, you mean chromatic aberration gets
    worse, not California...nevermind
    Wayne, May 10, 2007
  6. Zed

    Marvin Guest

    Mold would scatter light, and affect the resolution. It
    should not introduce CA. Ca is caused by the differences in
    the refractive index vs wavelength of each lens element.
    This is controlled by the choice of materials of the
    individual elements. It does not change with time.
    Marvin, May 10, 2007
  7. I have no idea if this could be a cause, but over time you can get a fair
    Thanks, that makes sense. It would be interesting to know more about the
    effects of repeated condensation cycles (and possible mold growth) in
    cameras over time, as in what's affected, and whether anything can be done
    about it. I suspect my pocketable digicams develop issues over time, due to
    carrying them in my rear jesey pocket while cycling, often on very hot days
    when it would be subject to a fair amount of condensation from sweat, and at
    other times, from dampness in the air.

    I probably don't want to think about the damage I do to my poor cameras...
    on the other hand, I've never had a failure in the field, and as I've taken
    many, many thousands of photos with each, it's not as if they haven't gotten
    a workout. But I've never tested them by shooting a test pattern when new
    and then another one down the road.

    --Mike Jacoubowsky
    Chain Reaction Bicycles
    Redwood City & Los Altos, CA USA
    Mike Jacoubowsky, May 11, 2007
  8. THe only thing I can think of that would increase chromatic aberration
    would be misalignment of the lens or a lens element due to a serious
    knock. If that happened you'd very likely to get asymmetric CA, i.e.,
    different at left nd right or top and bottom. With a properly aligned
    lens it ought to be good in the middle and degrade symmetrically
    towards the edges.

    But note that most cameras are built to take pretty serious knocks,
    e.g. the not uncommon nasty noise on a windy mountain summit of a
    dropped DSLR hitting rock :)
    Chris Malcolm, May 11, 2007
  9. Zed

    Zed Guest

    Thus spake John Smith:

    Looking for an excuse to upgrade? The Canon A710 is a very good P&S but the
    excuse I have for *not* upgrading is simply that I don't have the money or
    likely to have enough until next year. As for just getting more critical, I
    knew very early on that CA was one of this model's weaknesses from reading

    Looking through the photos taken on the Olympus, I'd say that CA has
    worsened. I didn't notice at 1st, probably because I never thought it was
    possible. I read a post (maybe on this very NG) that someone mentioned that
    CA has deteriorated on their camera. I made a mental note & that's all. It
    wasn't until I thought that it had got worse on mine that I thought about
    how it could happen. Autofocus will compensate for mechanical wear to some
    degree but I'm unwilling to dismiss that an increase in CA might be caused
    by this. It may not be the case but it sounds plausible to me. The camera
    has not sustained a knock & I've not heard that the sensors deteriorate with
    age alone.
    Zed, May 14, 2007
  10. Zed

    Mike Russell Guest

    Have you compared one of your earlier photos with a recent one of a similar
    subject, taken under similar conditions? That would seem to give a better
    answer than any guessing about your camera that any of us can do.
    Mike Russell, May 15, 2007
  11. Zed

    Zed Guest

    Thus spake Mike Russell:
    The problem here is that CA wasn't very consistent between shots over a
    short period of time hence my asking if others had noticed any degradation.
    As the consensus is no, I'll not worry too much about it - especially as my
    C4040 isn't used anymore & it's hardly bad on my Canon.
    Zed, May 21, 2007
  12. I have noticed slightly variable CA on my Nikon 8800. Also, the
    sharpness of the images can change a bit from shot to shot. By using a
    variety of techniques, I concluded that the likely explanation was the
    image stabilization. That is achieved by moving a lens element a bit,
    which means it can move a bit off-axis where the alignment is degraded.
    If I turn off the IS, all imgages are equally sharp and have the same
    low CA, but if I turn it on, I can see variable CA and sharpness of a
    kind I could interpret as a off-center element. If I simply turn off the
    IS and turn it on, the next image is likely to be better than the last
    one before. This is all a bit subtle and of no practical consequence,
    and maybe I'm fooling myself about the interpretation, but I was very
    careful and took lots of images to investigate this when I got some
    slightly puzzeling results comparing my 8800 to my new Canon SD700IS.

    Joseph Miller, May 21, 2007
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