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12-12-2013, 09:13 AM   #31
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QuoteOriginally posted by altopiet Quote
I see what you're saying, but no.... single shot mode, not even continuous focusing. If you look at the first set you'll see where the person is hanging the ribbon, or what ever it's called, around my son's neck, it's impossible to have changed anything in that time frame, same with the second set, look at the lady heading to the same man.... I just pressed the shutter button, released and pressed again immediately..
Then aperture blades... or the mechanism that engages the aperture blades... assuming the software runs properly...

12-12-2013, 09:21 AM   #32
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It's a brand new DA70, I'll do some further tests with it on both cameras, perhaps the problem is lens related...





12-12-2013, 11:28 AM   #33
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QuoteOriginally posted by altopiet Quote
If you look closely at the EXIF and photographs, you'll see that the 2 shots were taken from exactly the same position, virtually a second or 3 apart, with the same settings, center-weighted metering mode. As I've said in my previous post this is the first time I've experienced something like this in over 21000 clicks, with my K-30, and it is something I've never seen in over 50000 clicks with my K-x...If spot metering was involved I could understand it, but almost identical shots in center-weighted metering mode should not have such an effect when there is nothing that changes in the scene that could have such an effect on the exposure as far as I can see, or is it possible?
A few months ago I shot about 5000 photographs in one day, with a different lens, and not once did anything like this occur...?

EDIT: Just to be more clear, the photographs in both sets, were consecutive, and there were about 80 or so other, perfectly exposed photographs between the two sets...
I am not trying to argue any points with you, I am just trying to explain what could have happened and that I do not think it is a problem with your camera or lens. If it were then you would have more instances of this occurring based on your expressed use of this camera.

Looking at your exif settings sure you were at the same fstop and the same distance, in AV mode your camera will not arbitrarily select different settings without metering on something either lighter or darker prior to that shot for it to change, It doesn't matter how many other photos were taken all it takes is for it to meter on something different for that 1 shot in this case two shots. You were not in bright sunny conditions, according to what is showing in the photos there is a lot of varied lighting. I presume you were looking through your view finder, if so the view finder settings would have shown the changes occurring prior to taking the shot. As long as something is set to auto adjust then it will right up to the point of capture unless you lock the exposure. Had you have been using Live View I venture to say it would have shown you on it's screen. I haven't even asked what your DP settings were at.

I venture to say you could have used center weighted metering, put your camera in Tav mode, selected your use of F2.4 or 2.8 and selected the shutter speed the camera was telling you was appropriate for what it was metering and left it in Auto ISO your camera would not have taken those with the varied exposure that you are showing.

If you or anyone else think it's a problem with your camera's then I suggest you contact Pentax and send your camera's back to have them check them out. I for one do not think that is the case.

Last edited by Oldbayrunner; 12-12-2013 at 11:35 AM.
12-12-2013, 11:18 PM   #34
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I must apologize, I just discovered that the RAW setting in my viewer, Faststone, reverted to default embedded Jpeg when displayed, after I recently updated it. The exposure of the original RAW files is acceptable if the settings are taken into account. My problem seems to be the in camera Jpeg conversion which for some reason failed on the 2 shots I posted. I use natural +1 on contrast, all the other Jpegs were in order except those I posted...

12-13-2013, 07:47 AM   #35
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IMO It is not your jpeg conversion either....Hopefully, I guess the best way to try to explain your photos show the exposure you got is right for the camera's settings, is to supply outside examples. Using the exposure settings from your 1st & 2nd sets of photos, these are examples I got from a camera simulator set to brightly lit indoor lighting using the same exact Fstop, Shutter & ISO that are showing in your exif, not taking into consideration where or what your camera was metering on. Forget the subject matter and the focal distance used as that is not important. Look at the exposure & identical exposure settings, with the exception of the third example, to your photos at the bottom of the shots.

Simulated 1st shot.


Simulated 2nd shot


For the third photo the simulator wouldn't go to f2.4 or ISO 4000 so I used 2.8 and 3200 which would give you comparable exposure.


Your fourth photo was the same settings as the first one.

Had I have used my camera or any camera with the same settings I would have gotten the same results. Now I guess one could try to lay blame on their camera for selecting incorrect settings and rightly so but IMO as photographers it is up to us to control the camera's exposure settings to portray what it is we want to capture as closely as possible. Since the days of camera's metering and auto setting selection ability it is a given it will not meter and select the correct exposure settings 100% of the time leaving it up to us to check and correct those settings, lock the exposure or manually set them up prior to shooting.

Last edited by Oldbayrunner; 12-13-2013 at 08:02 AM.
12-13-2013, 08:14 AM   #36
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QuoteOriginally posted by Oldbayrunner Quote
IMO It is not your jpeg conversion either....Hopefully, I guess the best way to try to explain your photos show the exposure you got is right for the camera's settings, is to supply outside examples. Using the exposure settings from your 1st & 2nd sets of photos, these are examples I got from a camera simulator set to brightly lit indoor lighting using the same exact Fstop, Shutter & ISO that are showing in your exif, not taking into consideration where or what your camera was metering on. Forget the subject matter and the focal distance used as that is not important. Look at the exposure & identical exposure settings, with the exception of the third example, to your photos at the bottom of the shots.

Simulated 1st shot.


Simulated 2nd shot


For the third photo the simulator wouldn't go to f2.4 or ISO 4000 so I used 2.8 and 3200 which would give you comparable exposure.


Your fourth photo was the same settings as the first one.

Had I have used my camera or any camera with the same settings I would have gotten the same results. Now I guess one could try to lay blame on their camera for selecting incorrect settings and rightly so but IMO as photographers it is up to us to control the camera's exposure settings to portray what it is we want to capture as closely as possible. Since the days of camera's metering and auto setting selection ability it is a given it will not meter and select the correct exposure settings 100% of the time leaving it up to us to check and correct those settings, lock the exposure or manually set them up prior to shooting.
I never mind learning new stuff, lucky for me I was not the event photographer, just a proud dad at his son's university graduation...
12-13-2013, 08:35 AM   #37
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QuoteOriginally posted by Oldbayrunner Quote
IMO It is not your jpeg conversion either....Hopefully, I guess the best way to try to explain your photos show the exposure you got is right for the camera's settings, is to supply outside examples. Using the exposure settings from your 1st & 2nd sets of photos, these are examples I got from a camera simulator set to brightly lit indoor lighting using the same exact Fstop, Shutter & ISO that are showing in your exif, not taking into consideration where or what your camera was metering on. Forget the subject matter and the focal distance used as that is not important. Look at the exposure & identical exposure settings, with the exception of the third example, to your photos at the bottom of the shots.

Simulated 1st shot.


Simulated 2nd shot


For the third photo the simulator wouldn't go to f2.4 or ISO 4000 so I used 2.8 and 3200 which would give you comparable exposure.


Your fourth photo was the same settings as the first one.

Had I have used my camera or any camera with the same settings I would have gotten the same results. Now I guess one could try to lay blame on their camera for selecting incorrect settings and rightly so but IMO as photographers it is up to us to control the camera's exposure settings to portray what it is we want to capture as closely as possible. Since the days of camera's metering and auto setting selection ability it is a given it will not meter and select the correct exposure settings 100% of the time leaving it up to us to check and correct those settings, lock the exposure or manually set them up prior to shooting.
Yes, any camera meter might produce a non-desired result sometimes but such under and over-exposure in the graduation photos surely seems to indicate a fault occurred somewhere. Those aren't the occasionally expected metering errors that pop up every now and then.
12-13-2013, 08:47 AM   #38
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And rightfully so.... Looking at that 2nd photo I really feel for you because it happened on one of those moments that can't be re-captured so for you I hope the event photographer got one you can obtain and enjoy.

12-13-2013, 09:02 AM   #39
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Ok, just for clarity, a screen shot of the 4 images, with exif included...RAW at the bottom, camera JPEG on top...

I know now I should've taken a test shot and lock exposure....but it still is interesting how the camera jpeg exposures on the 2 different sets,actually went in opposite directions...
Attached Images
 
12-13-2013, 11:08 AM   #40
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QuoteOriginally posted by IchabodCrane Quote
Yes, any camera meter might produce a non-desired result sometimes but such under and over-exposure in the graduation photos surely seems to indicate a fault occurred somewhere. Those aren't the occasionally expected metering errors that pop up every now and then.
Sure I would agree, I have had it happen on rare occasion with a few cameras where I failed to take notice of the settings and had a few shots meter/expose similar and not just with digital slr's. My main contention is those exposure settings would have shown in the view finder and could have been corrected prior to the shot or pre setting up the camera to use the correct exposure settings for the aperture and the EV lighting could more than likely prevented it from happening. Now did the metering go way off for some reason yep, if it happened often then I would say there is a problem with the camera.

Personally I think the best meter is ones eyes and knowing, or using an exposure chart to know, what comparable exposures are suitable for the EV lighting you are in. Then do either A. select the settings for that EV with adjustments based on what's suitable for your needs to capture your subject as you envision it or B. by checking to see if the camera is metering and correctly selecting settings for that EV lighting and making exposure adjustments for what you want or C. if your not completely sure Bracket expose. I'm old school so I constantly have to remind myself to fall back on what I learned and had to use a long time ago, It"s too easy for me to be lax letting the camera make the exposure decisions and when I let that happen I usually wind up not completely happy with some of the results
12-13-2013, 12:14 PM   #41
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QuoteOriginally posted by altopiet Quote
Ok, just for clarity, a screen shot of the 4 images, with exif included...RAW at the bottom, camera JPEG on top...

I know now I should've taken a test shot and lock exposure....but it still is interesting how the camera jpeg exposures on the 2 different sets,actually went in opposite directions...
Well if these are truly how these photos came off your camera with no adjustment what so ever besides reduction then you do have a problem because there is no way a photo taken in raw and a photo taken in jpeg using identical exposure settings of the same identical subject would come out that different without some processing. The top ones are representative of what the exposure should relatively come out like given the settings used, that I know for a fact.
12-13-2013, 12:47 PM   #42
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As the camera is out of warranty period, I'll just carry on and keep an eye on it, trying other lenses etc. At least with all the info I have now, I know what to look out for, and I must say, I might've become a bit lazy, letting the camera do all the thinking for me...





12-13-2013, 01:50 PM   #43
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Lol...Dont we all from time to time
12-13-2013, 04:08 PM   #44
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QuoteOriginally posted by altopiet Quote
As the camera is out of warranty period, I'll just carry on and keep an eye on it, trying other lenses etc. At least with all the info I have now, I know what to look out for, and I must say, I might've become a bit lazy, letting the camera do all the thinking for me...
Are the shots still on the SDHC card? If yes, consider putting it back into the camera and looking at the two shots on the camera LCD to see if they still appear over and under exposed, respectively. If by some chance they look normal, then it could be a flag that's being misinterpreted by your image processing software.
12-13-2013, 10:52 PM   #45
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QuoteOriginally posted by IchabodCrane Quote
Are the shots still on the SDHC card? If yes, consider putting it back into the camera and looking at the two shots on the camera LCD to see if they still appear over and under exposed, respectively. If by some chance they look normal, then it could be a flag that's being misinterpreted by your image processing software.
I've still got it on the card, but unfortunately the shots displays on the camera with the same problems...
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