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12-18-2008, 01:28 PM   #1
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Weird K10D underexposure problem

A couple of weeks ago, my K10D started randomly producing shots that were 2-3+ stops underexposed. The camera has a little under 4k shutter actuations, and is coming up on being a year old.

Here's what happens: I meter a scene and select my exposure settings in M or Av. I depress the shutter and right before the mirror flips up the camera makes a brief noise that somewhat resembles a windup toy in action. The picture comes back massively underexposed, I delete it and the next picture I take is fine.

I haven't been able to nail down a trend to when this happens. I've experienced it with a couple lenses and under different lighting conditions. My two guesses are that either the aperture lever is stopping the lens down too far, or that the shutter is firing before the mirror flips up.

Anyway, I just though it was weird and was wondering if anyone has ever heard of a problem like this. I'm still under warranty and was planning on sending my camera in after the holidays for calibration and cleaning anyway, so hopefully I should be fine whatever it is.

12-18-2008, 02:34 PM   #2
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I don't think this is what is happening in your case, but I had this happen a while back, and found that after consuming a couple of glasses of wine, I was pressing the exposure compensation button with my thumb instead of the AF button, and then adjusting exposure instead of aperture.
12-18-2008, 02:42 PM   #3
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I have the same problem when I do motocross racing. Same framed area, same lighting, same metering, but one out of every 4 or 5 come out anywhere from 2-5 stops underexposed, never over. sometimes its 2 or 3 photos in a row, then the next few are fine. Usually during these sequences, my eye isnt even leaving the viewfinder.

However, I rarely run across this issue when I am walking around taking the occasional photo.
12-18-2008, 02:54 PM   #4
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This is a total stab on the dark....but have you tried cleaning the contacts on the lens & body?

No science in that, just a wild guess.

12-18-2008, 03:10 PM   #5
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QuoteOriginally posted by GeneV Quote
I don't think this is what is happening in your case, but I had this happen a while back, and found that after consuming a couple of glasses of wine, I was pressing the exposure compensation button with my thumb instead of the AF button, and then adjusting exposure instead of aperture.
Heh, yeah, I still use half-press for focus. It's annoying for times when I just want to snap off a quick picture of something at infinity. If it weren't for the manual focus switch on the body/lens I'd probably map focus to the AF button.

In any event the underexposed shots happen randomly without the exposure setting changing. I've had times when shooting in M under low light when the camera took an entirely black frame. I tried the shot again and got a proper exposure. Rarely it happens twice in a row, but usually it's just an isolated incident. Lately it seems to be happening to me once or twice every time I go shooting.
12-18-2008, 03:12 PM   #6
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QuoteOriginally posted by Mallee Boy Quote
This is a total stab on the dark....but have you tried cleaning the contacts on the lens & body?

No science in that, just a wild guess.
This is a pretty good idea actually, come to think of it. I'll give it a shot and bump this thread from the dead in a week or two to report if I have the problem pop up again or not.
12-18-2008, 03:15 PM   #7
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QuoteOriginally posted by Kirivon Quote
Heh, yeah, I still use half-press for focus. It's annoying for times when I just want to snap off a quick picture of something at infinity. If it weren't for the manual focus switch on the body/lens I'd probably map focus to the AF button.

In any event the underexposed shots happen randomly without the exposure setting changing. I've had times when shooting in M under low light when the camera took an entirely black frame. I tried the shot again and got a proper exposure. Rarely it happens twice in a row, but usually it's just an isolated incident. Lately it seems to be happening to me once or twice every time I go shooting.
My gues is shutter is starting to fail/sticking... Definitely send it in for servicing...
12-18-2008, 06:13 PM   #8
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QuoteOriginally posted by Kirivon Quote
"under different lighting conditions".
Stab in the dark - one of those technique things that some folks forget - if light enters the viewfinder it can effect the exposure - most notably if you have the sun to your back/over your shoulder. Just a guess. Ken.

12-18-2008, 06:54 PM   #9
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QuoteOriginally posted by bbpa103 Quote
Stab in the dark - one of those technique things that some folks forget - if light enters the viewfinder it can effect the exposure - most notably if you have the sun to your back/over your shoulder. Just a guess. Ken.
The metering is fine, the issue is that the camera won't match the meter. I.e you set an exposure manually, you get a black frame, then you take the picture again with the same settings and get a properly exposed image.

I think Mallee's suggestion may have sorted it out. I fired off 65 exposures at my wall after cleaning the contacts on my body and lenses. None of the shots came back with the problem. I won't declare the issue 100% resolved until I take some more shots in the field, but the possibility that my contacts were dirty fits in with my earlier hypothesis that the aperture was being stopped down too far.
12-19-2008, 04:54 AM   #10
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QuoteOriginally posted by bbpa103 Quote
Stab in the dark - one of those technique things that some folks forget - if light enters the viewfinder it can effect the exposure - most notably if you have the sun to your back/over your shoulder. Just a guess. Ken.
That is a good possibility, I never thought of that. I did not encounter that problem at an indoor race at all. The only under exposures came when the flash did not fire (quick shooting without enough time for the flash to regenerate). I will have to pay more attention to that next time out, unfortunately, I will have to wait until April for that.
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