long exposure problems...

Discussion in 'Digital Photography' started by seenew, Dec 10, 2005.

  1. macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #1
    As I previously posted, I just got a Nikon Coolpix 8800. Everything has been fine with it; no problems. However, last night I tried out some long exposures on it for the first time. I wanted to shoot the clouds moving across the moon, so I used the slowest shutter speed-- 10 minutes. BUT, after the picture was taken, I looked at it, and the whole thing had a pink tint to it, and there was a pink light bleeding over into the top-right portion of the frame. Disturbed, I took another shot, waited ten minutes, got the same thing.
    I zoomed in on the moon and took another shot, and the pink was less visible in one shot, and completely absent in another.
    So, I took the camera inside and decided to do a trial under a controlled environment. I set up the tripod in my hallway, closed all the doors and cut out the lights, so it was completely dark, except for my Nintendo DS, which I was using as a light source for the experiment. Took a ten minute shot, got the SAME PINK LIGHT. I set the aperture to 8.0 from 4.0 and tried again. Same thing, just darker.

    Does anyone know how to fix this, or has anyone heard of it? I am really stressing out, because I got this camera off eBay, and the owner said she got it in January of this year, and that it had a one-year warrenty. However, I don't know how to transfer that to me, or if maybe she didn't register it, and I should, and see if Nikon can fix it...

    Any help is greatly appreciated, here are some sample shots:
    [​IMG]
    f4.0^

    [​IMG]
    f8.0^
     
  2. g^3
    macrumors member

    Joined:
    Sep 24, 2005
    #2
    did you try changing the white balance. maybe try different settings such as night scene, etc....
     
  3. -hh
    macrumors 68020

    -hh

    Joined:
    Jul 17, 2001
    Location:
    NJ Highlands, Earth
    #3
    Color shift during long exposures was a known element to have to manage with traditional film.


    It would appear that the issue hasn't gone away with the change to digital, although it should be a lot easier to do the color correction.


    Your best recourse is to not take such long exposures if you can get away with it, and avoid the color shifting. Outdoors, the moon moves a lot faster than what one would otherwise suspect - - I can recall taking some telephoto photo's of a lunar eclipse a few years ago and anything longer than around 30 seconds (IIRC) was uselessly blurred.



    -hh
     
  4. thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #4
    Okay, thanks a lot for the help. I'm just glad the camera isn't broken or anthing. The people over at the dpreview.com forums also suggested it might be infrared light that shows up only at this long of an exposure. My guess is it's a combination of both your theories.

    Again, thanks for setting my mind at ease. :)
     
  5. thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #5
    I figured it out. It was infrared light, after all. I had been using the remote to take the shots, instead of the timer. The remote or the reviever or both caused the pink light. :) I fixed it, and now the shots are great. Thanks for all the help, guys! :D
     
  6. -hh
    macrumors 68020

    -hh

    Joined:
    Jul 17, 2001
    Location:
    NJ Highlands, Earth
    #6
    Dang, I forgot about IR...sorry about that. I knew that that IR filters commonly exist on current "video" cameras and I didn't do the "1+1" to realize that this would logically also apply to the sensors in digital still cameras too.

    BTW, I happened to be clearing out a stack of fairly recent "Mac Addict" magazines this past week and noticed a "How To" article that detailed how to take apart a USB web camera to remove its IR filter as one of the steps to convert it from a visible light to an IR camera.

    Overall, what this is telling us is that these CCD/CMOS sensors will collect photonic energy from the IR spectrum, which for conventional (eg, visible light) images could under some conditions be highly undesirable from a Signal:Noise perspective, as you illustrated.


    -hh
     

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