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03-04-2013, 11:30 PM   #1
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K20D underexposure

I have been using the K20D for a while now and have got to like it. I was on a long photo outing recently shooting mostly landscapes. One problem I noticed was underexposure on many of my landscapes. These were typically shot early in the morning (6 to 7 AM) when the light was just coming out. I figure the images were underexposed by as much as a full stop, sometimes even more. Is this is generic problem with the K20D or is it just me? Has anybody experienced this problem and any tips to overcome? Lost a number of good shots because of the underexposure.

I shoot RAW, and have set the camera to record in DNG format. The file size for a 15 MP camera is quite large (~24 MB). However, when I used the Adobe RAW converter on these files the output was much smaller (~14 MB). Quite a saving when you consider literally 10 of thousands of images. Before I run the converter on all my images, would like to know if any important information will be lost and hence will the image quality suffer. Unfortunately, this is a one way street and there is no possibility of getting back the original DNG as shot by the camera. If there is no loss in quality, I wonder why Pentax does not use the compressed format.

I also used the Pentax 28-200 on this outing. What I notices was that the images were way too soft, even when the lens was stopped down. That crispness of the landscape was entirely missing rendering the image useless. I have been using this lens with my film SLR too. Any similar experience?

mj

03-05-2013, 12:00 AM   #2
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I have using K-20D for about 4 years now, and I always set the Exposure Compensation at +.7 to get correct exposure. About the Pentax 28-200, I used to have one and I did not like it bacause it was not a sharp enough lens .
03-05-2013, 12:53 AM   #3
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Same experience here with the K20D. Often shoot with the DA16-45 and the combination always underexposes. I also add +7 compensation for landscapes and other 'average' situations. I use Raw and Photoshop CS5.1 to process - allegedly the camera is set up this way in order to never blow out highlights.
03-05-2013, 12:55 AM   #4
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I have been trapped a few times with badly exposed photos because I accidentally left the camera set to multi segment metering mode.

03-07-2013, 12:12 AM   #5
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Thanks for confirming the underexposure "feature" of the K20D An exposure compensation of 2/3rd stop used selectively should take care of the issue.

My other query about the DNG file size has no answers! Any body who can share some information about this?

mj
03-07-2013, 02:14 AM   #6
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Hi mj,

just make a copy of the folder on your PC where the DNG files are so you allways have a copy. then process the other files.
03-07-2013, 05:36 AM   #7
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QuoteOriginally posted by Billgscott Quote
Hi mj,

just make a copy of the folder on your PC where the DNG files are so you allways have a copy. then process the other files.
Thanks. I can do that. However, my question is whether I can delete the original (bigger) files without worrying about losing any image quality. I would not like to keep two copies of the same image especially when the idea is to save space by converting to smaller files.

mj
03-07-2013, 08:12 AM   #8
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QuoteOriginally posted by mmjoshi Quote
I would not like to keep two copies of the same image especially when the idea is to save space by converting to smaller files.

mj
Memory is cheap, memories are priceless. Keep the original .dng and the final processed image. That way you can allways go back.

I got a 32GB memory card for my phone(!!!) the other week at 20. When I looked at getting a 64KB memory chip for my first PC in '92 it was 128. When you look at that, memory is wayyyy cheap.

Bill

03-08-2013, 06:08 AM   #9
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File sizes

QuoteOriginally posted by mmjoshi Quote
My other query about the DNG file size has no answers! Any body who can share some information about this?

mj
The K20 produces DNG without any compression. So they are very large, if you generate PEF files they use lossless compression and so are large; 15Mbytes typicaly.
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