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06-14-2010, 09:37 AM   #1
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Shake Reduction/Over Exposed Images Problem

K7/Sigma 18-250 - Over exposed images and shake reduction problem?

When shooting, images in the viewfinder seem to take too much time to settle or stop moving around or stop jostling around as the SR system stabilizes and solidifies the image. At least I think that it is the SR system.

The result, frequent over exposed images when I try to shoot quickly and don't wait for the image to stop jiggling a bit in the viewfinder. Frustrating.

As a result, I can't shoot quickly with confidence.

06-14-2010, 10:04 AM   #2
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What mode are you shooting in?

I have never had an issue with over exposing due to SR, i've probably shot close to 40,000 using it by now.
06-14-2010, 10:21 AM   #3
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If you are talking about the Sigma 18-250 with IS, yes it does take a bit longer than the using the in-body SR. My Sigma typically takes about 1/2 - 1 second. Make sure you do not have the lens IS and the camera's SR both turned on.

Any exposure problems are unrelated to IS/SR.

Last edited by Parallax; 06-14-2010 at 11:43 AM.
06-14-2010, 10:32 AM   #4
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Stabilization or no stabilization, the shutter is only open as long as the camera says it is. So as Jim says, if you're seeing overexposure, that's something else. It would help to post an example, with EXIF intact so we can see your camera settings. Most likely it's a question of using an inappropriate metering mode for the subject as framed, an inappropriate amount of exposure comensation for the subject as metered, etc.

06-14-2010, 11:33 AM   #5
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Thanks

I want to thank each of you for taking the time to respond. I really appreciate it.
I'm just learning the camera and am no expert so it could be me making a mistake...but in auto and P modes I didn't think there were all that many settings I could be messing up that would cause this problem.


Thanks again!!


Gaelen - was shooting in auto/green and P burst mode yesterday at a college graduation

Parallax - Very interesting about conflict between in camera and the SR in lens in the Sigma 18-250. I will turn off each one at a time and experiment. Maybe this is the problem.

Marc - a friend is borrowing my camera today and I deleted in-camera, the over exposed images so don't have any to post. I will get the camera back and try to replicate.

Question though??? But since I am shooting in green/auto metering mode, shouldn't the camera automatically be handling the SR and exposure issues flawlessly? Just FYI re subject - outdoor setting at a college graduation, no flash, partial sun
06-14-2010, 01:20 PM   #6
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The last thing you can expect from green mode is flawless metering. The camera's meter assumes that the scene presented to it averages out to 18% gray. (This is true for all cameras, it is not Pentax-specific.) But not all scenes average out to 18% gray.

Two examples: A snowy field in the winter. The actual scene has a lot of white in it, but the camera meter expects to see 18% gray, so it will underexpose and you will get gray snow. A portrait of a black labrador retriever. The actual scene has a lot of black in it, but the camera meter expects to see 18% gray, so it will overexpose and you will get a gray labrador retriever.

You need to know when and how to override the camera's metering system. Here is a good site for learning how to do this: Ultimate Exposure Computer
06-14-2010, 06:26 PM   #7
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QuoteOriginally posted by Parallax Quote
If you are talking about the Sigma 18-250 with IS, yes it does take a bit longer than the using the in-body SR. My Sigma typically takes about 1/2 - 1 second. Make sure you do not have the lens IS and the camera's SR both turned on.

Any exposure problems are unrelated to IS/SR.
This is most likely the cause for the 1-2 seconds it is taking to "stabilize", the redundancy of the IS on the lens and the camera trying to use SR is why you cannot shoot at a fast pace and as for the over exposed that is most likely another setting. Be careful because in P mode and AutoPict you can still set your EV to over/under expose. That may be your problem.
06-14-2010, 07:16 PM   #8
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QuoteOriginally posted by Jeff Lowe Quote

Gaelen - was shooting in auto/green and P burst mode yesterday at a college graduation
I believe that would be your issue over the lens....

Auto meter is RARELY ever completely accurate, no matter what body/lens you are shooting. Your best bet is shoot in M with situations you are worried about. I dont shoot anything in any auto modes anymore.

06-15-2010, 08:52 PM   #9
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Overexposed Photo Samples

I found some examples of overexposed shots. I've never uploaded photos here before so don't know if you will be able to see them.
Attached Images
         
06-15-2010, 09:03 PM   #10
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With that level of dramatic over-exposure, I would say you have left your Exposure Compensation on, and had it set at something extreme.

It happened to me a while ago - two whole days of over-exposed shots with my K200D because by default the camera 'remembers' the exposure compensation from one shooting session to another. If you shot in RAW, you could probably salvage those pictures quite decently though.
06-15-2010, 09:51 PM   #11
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That is definitely the Exposure Value being set to almost the max. What mode are you shooting in? EV can be controlled in most modes. If you are shooting in M than its a different problem.
06-16-2010, 02:38 AM   #12
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exif data would help in figuring out what went wrong.
06-16-2010, 10:06 AM   #13
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Yes, these are clearly either exposure compensation being turned up (in other words, you *asked* the camera to overexpose), or else you were using spot metering but didn't point the camera directly at a part of the scene for which spot metering is appropriate. As others said, without EXIF, we can't really say which. But in any case, setting exposure compensation back to zero and switching back to multi-segment metering will fix this. Exposure compensation and spot metering are both useful tools, but only if you know how and when to use them.

Last edited by Marc Sabatella; 06-16-2010 at 04:49 PM.
06-16-2010, 10:31 AM   #14
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QuoteOriginally posted by MPrince Quote
exif data would help in figuring out what went wrong.
Critical as a matter of fact.

I had a few shots like that on my recent trip. It turned out I had left the camera set to ISO 1600 and AV with the aperture near wide open. The camera had nowhere to go to make the exposure work outside. The exposure data flashing on the back screen told the tale immediately.
06-16-2010, 04:51 PM   #15
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Ah, yes, forgot that this is another possible explanation. If you've got ISO set high and aperture set large, the camera might be limited by it's maximum shutter speed. Again, posting pictures *without* stripping EXIF info is the solution. I know, next question is, how to preserve the EXIF info. That's a question for the manual that came with whatever softwar you used to resize or otherwise process the images before posting. The EXIF info was there when you shot, but somehow you stripped it out before posting.
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