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01-05-2011, 10:27 AM   #1
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Horribly overexposed images K10 in bright natural light

Greetings: would love some insight on the following:

I have had 2 instances (separated by about 1 year) of the following:

Using K10d in bright, outdoor lighting, horribly over exposed images (see uploaded image).

It has happened with 2 different lenses. First time was hot weather, 2nd time was cold weather.

The 2nd time it occurred, my camera was also incorrectly telling me my (brand new) memory card was full (I put it in another of my pentax bodies and it had space and allowed me to take more photos). Also, I noticed that this time the image file that resulted was much smaller than it should have been. (I was shooting a wedding and using max image size). The dng files appear to be the correct size but the jpgs are smaller than they should be. The uploaded images were shot with a Pentax FA-50 1.4 at 2.8, iso=100 and at iso=400 (same lens etc.)

Any idea what it is? The first time it happened I had just gotten a new 2nd hand lens and thought that may have been the problem. I went back to the shop that sold me the lens, they replaced it and thought maybe my sensor was going. This time I was using a new 16 gig card and a pretty new fast lens. First I thought it was the card but the card seemed to work fine in the other body I was using that day and I've used the lens on other occasions without trouble. I called a camera repair place and they thought it might be a problem with the circuit board writing to the card.

This time I thought maybe it was maybe because I was shooting a fast lens open in bright light, but I checked and it wasn't wide open and it also happened at both 100 and 400.

Any thoughts or insights appreciated.

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01-05-2011, 10:49 AM   #2
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Shutter Speed for these shots?
01-05-2011, 10:52 AM   #3
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Hi....first thing that came to my mind was that your aperture on the lens doesn't close....but even so...that is too heavy overexposure for two stops difference - if you were using F2.8 on FA50 1.4.
Second thought was that you might have dialed positive exposure compensation. Or you took spot metering from the black suit. Or simply u had wrong user mode dialed in....like Manual mode with slow shutter speed, possibly...
Well some suggestions: Try another lens if you have any. Look out for exposure compensation. Try to change metering mode to center-weighted or matrix metering. Reset K10d to factory settings. If everything fails I would take it to the service.
01-05-2011, 11:47 AM   #4
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Can you post a Full unmodified EXIF from one of these images (as out of camera) or upload an unmodified file somewhere? We may be able to pick it apart from there. Clearly, it would appear that the lens didn't stop down for your exposure. One reason that These JPGs might be so small compared to what you are use to, is that there is so much White space. Also, I'm wondering if the 16Gb card is too big for the K10d (did you update the camera to v1.31? firmware?).



01-05-2011, 01:14 PM   #5
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Hi- some details about the shots:
all images w/ Pentax FA 50 1.4.
image 1: 1/125; exposure program not defined; f 2.8 iso=100; pattern metering
image 2: 1/4000; aperture priority; f 1.7; iso=400; pattern metering; auto exposure and white balance; normal contrast, saturation & sharpness.
image 3: 1/180; aperture priority; f 2.8 iso=400; pattern metering; auto exposure; manual white balance; scene capture standard, normal contrast, saturation, sharpness

The only difference I could find between the pictures immediately proceeding these or those after which were not problematic are as follows:

in image 1, the exposure program setting in the exif data reads not defined, which seems odd to me;

in one of the images I didn't upload which failed, the white balance was set to manual which is odd since I never alter the white balance settings and I would have thought that the aperture priority and other programs would have over-ridden a manual white balance-- so now I am wondering if there is a bug in the white balance or aperture software.

As near as I can tell on the problematic images, it seems to have defaulted to a manual white balance (though this is only evident in some of the images-- I suspect the dng files, as the exif data on some of the images lacks data re: white balance).

The only settings I altered though while shooting were my aperture and iso-- I left my camera on aperture priority the entire time.

Re: the 16 gig card- it worked for the most part.
Camera appears to have not been using v 1.3 firmware, so I have now done that upgrade.

does anyone know how to copy complete exif data out of either ps cs3 or elements? If so, I can post full exif data for both the dngs and jpgs.

thanks for the comments!
01-05-2011, 02:22 PM   #6
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check all your knobs and switches esp the metering mode

I had a similar problem and it turned out to be that the switch that toggles between the different metering modes was not quite on center-weighted, it was just slightly out of the detent position, so it looked ok but really wasn't. So check that by actually moving the switch around. While your at it might as well check the mode dial, and the others, it certainly can't hurt

NaCl( are you sure there wasn't a small thermonuclear explosion? )H2O
01-05-2011, 02:47 PM   #7
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---------- Post added 01-05-11 at 04:30 PM ----------

QuoteOriginally posted by geek-girl Quote

I have had 2 instances (separated by about 1 year) of the following:

Using K10d in bright, outdoor lighting, horribly over exposed images (see uploaded image).
I really don't think that two images separated by a year qualifies as an actual problem.

Last edited by Ira; 01-05-2011 at 04:30 PM.
01-05-2011, 05:48 PM - 1 Like   #8
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The second photo looks like the camera ran out of shutter speed for the settings you were using. Aperture priority, f/1.7 and ISO 400 called for a shutter speed higher than 1/4000 and the camera couldn't provide it. Dropping down to 100 ISO would have helped, but you still may have needed either a neutral density filter or a smaller aperture.

1 and 3 also look grossly over exposed, but there isn't enough exif data posted to diagnose what the problem was. If you hit the exposure lock button while metering a darker area and didn't re-meter for the brighter conditions that could have caused the problem. If you had the camera in a forced flash mode that might explain the 1/180 shutter speed on 3, even though you were using aperture priority.

01-06-2011, 01:45 AM   #9
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If you put the camera in full auto (it selects ISO, aperture and shutter speed) does it have a problem? If not I suspect it's something to do with your settings.
01-06-2011, 05:27 AM   #10
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My reaction is similar to steinbacks. For what ever mode you were in the camera could not adjust within the limits of exposure

I have found that with fast lenses there is not a low enough ISO setting to use them at large apertures in bright sunlight

Recall the sunny 16 rule shutter speed = 1/ISO at F16

You are not there in any of these shots

My bet is operator error Sorry
01-06-2011, 06:00 AM   #11
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I support Lowell in his diagnostic. You were having an aperture way to large for the lighting conditions, especially when using ISO 400.
01-06-2011, 12:05 PM   #12
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QuoteOriginally posted by geek-girl Quote
image 1: 1/125; exposure program not defined; f 2.8 iso=100; pattern metering
Strange. Good theory by Steinback about hitting AE-L by mistake, but another one could be that the exposure program was set to manual. Strange it reads "not defined".

QuoteOriginally posted by geek-girl Quote
image 2: 1/4000; aperture priority; f 1.7; iso=400; pattern metering; auto exposure and white balance; normal contrast, saturation & sharpness.
I agree with Steinback on this one. Too wide aperture and too high ISO for bright daylight in Av @ f/1.7, and you ran out of shutter speed.

QuoteOriginally posted by geek-girl Quote
image 3: 1/180; aperture priority; f 2.8 iso=400; pattern metering; auto exposure; manual white balance; scene capture standard, normal contrast, saturation, sharpness
Hmmm... 1/180? Was this one taken with flash? 1/180 in Av @ f/2.8 and ISO 400 in broad daylight should wash it out.

Looks good to me, your camera is most likely working fine.
01-07-2011, 01:36 AM   #13
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Thanks for many great comments. Some more of my thoughts follow:

it is remotely possible I could have hit the AE lock by mistake-- but this seems unlikely as in at least 1 case the images after the problem image were same subject matter and not problematic.

I wasn't using any manual settings-- at least not intentionally. As NaClH2O suggests though, the knob could have been between settings though this too seems unlikely as were this the case one would expect the subsequent images to contain the same item in the exif, which it didn't.

Re: user error-
Definitely true that I should have dialed down my iso- the lighting conditions had changed rapidly and I got caught up in shooting (it was a wedding) and didn't immediately adjust the ISO, so at least in the case of the image that was at 1//4000 of a second, that was a contributing factor.

Re: Flash- it wasn't on for any of the images and settings on flash compensation were normal for all settings. On ne of the images I uploaded and at least one from a year ago, it indicated that the flash was suppressed.

re: cats_five question re: does this happen in full auto-- I can't tell from these images and can't necessarily find out now because a) it won't be sunny in beautiful Whistler BC til Monday probably (but we have great skiing at the moment), and b) the problem is very intermittent. However, it does appear from one of the images from a year ago that indeed it did happen in full auto (see below).

I too wondered if part of the problem was what Lowell suggested re: fast lenses not being able to go low enough in ISO settings.

I just checked one of the images that overexposed from a year ago and it was shot at 1/30; f=5.6; iso=100 focal length 300 on a pentax FA 100-300 4.7-5.8 lens. Camera was in auto exposure mode, and exif data suggests flash was compulsory but did not fire, patterned metering, auto white balance, and nothing else odd. Looking at this other image's exif data from a year ago makes me think the issue may be related to firmware or metering (because this lens was at low f stop, camera setting at a low iso). The fact that it did happen in full auto mode with varied lenses (some fast, some not), even in the absence of user error (iso was correctly set on some of the images from this year as well as last year's) makes me think that it is a firmware glitch or metering problem.

Of course I'll welcome any other thoughts. Will try to dig out the additional year old over-exposed images and review exif data on those as well to see if I can discern a pattern....

Last edited by geek-girl; 01-07-2011 at 01:52 AM.
01-07-2011, 02:07 AM   #14
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QuoteOriginally posted by geek-girl Quote
Of course I'll welcome any other thoughts. Will try to dig out the additional year old over-exposed images and review exif data on those as well to see if I can discern a pattern....
If you find them it would be great if you could post them with EXIF intact. There is some 100 parameters hidden there, most are irrelevant but who knows which one may hold some clues.
01-07-2011, 02:34 AM   #15
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In my experience AE lock is only applied to the first image taken after it is pressed. The idea is that you meter on the most critical part of the image, lock exposure, recompose, take the photo and then the camera returns to the metering mode it was in previously. I believe that it shows up as a line item in EXIF.

Do you have a grip on the camera? I find that having the grip installed and turned on when it is not in use can make it easier to hit controls accidentally.

Depending on how you upload photos, some free hosting sites like Flickr leave EXIF data intact even if you only make small sizes of the photo available for public viewing.
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