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03-15-2009, 08:39 AM   #1
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Gradiation - K20d

I took this shot on Wednesday and am a bit puzzled. None of the other images exhibited this, but with this one particular image, there is a very very poor gradiation in the sky. I know that it wasn't a great shot to begin with, but that shouldn't effect the number of colors in the sky. Attached is a screen shot of PPB with the EXIF on the bottom.

Any ideas as to why this would have occurred?


Last edited by code4code5; 07-16-2009 at 09:29 PM.
03-15-2009, 08:44 AM   #2
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This is a shot of just the sky?
I'm not sure this is the best way to illustrate if there's a problem with your camera.
Try a real life shot, like a landscape, and if the blue graduates.
Here, it may just be that the frame just captures the sky vertically above, which then won't have any graudation in colour - it's really when a more oblique or horizontal aspect including the sky that you'll get graduation.
03-15-2009, 09:04 AM   #3
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I suspect, as this is a screenshot, that the banding is your monitor not displaying all of the colors that were captured. Try exporting the picture as a tiff or jpeg with 8 bit color depth and see if that displays differently.
03-15-2009, 09:36 AM   #4
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QuoteOriginally posted by Ash Quote
This is a shot of just the sky?
I'm not sure this is the best way to illustrate if there's a problem with your camera.
Try a real life shot, like a landscape, and if the blue graduates.
Here, it may just be that the frame just captures the sky vertically above, which then won't have any graudation in colour - it's really when a more oblique or horizontal aspect including the sky that you'll get graduation.
There's much more to the picture than that. The clip is a 100% crop of the image. None of the others displayed the issue.

Thanks for the heads up though. When I exported the image into a different file format, I didn't see the issue. It's just strange that the PDF looks like that.

03-15-2009, 09:38 AM   #5
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Looks like you cleaned your sensor and left streaks.
03-15-2009, 09:40 AM   #6
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Is this before any processing? If you've run things like shadow/highlight recovery, colour channel mixer and so on, you will get this type of issue a lot.
03-15-2009, 09:55 AM   #7
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QuoteOriginally posted by Peter Zack Quote
Is this before any processing? If you've run things like shadow/highlight recovery, colour channel mixer and so on, you will get this type of issue a lot.
Nope... This is a crop of the straight PEF without any processing in Pentax Photo Browser. I've only had my K20D for three weeks and haven't even looked at the sensor. It makes me wonder if my SD card isn't beginning to fail, seeing how it was only the one shot.
03-15-2009, 10:18 AM   #8
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QuoteOriginally posted by code4code5 Quote
Nope... This is a crop of the straight PEF without any processing in Pentax Photo Browser. I've only had my K20D for three weeks and haven't even looked at the sensor. It makes me wonder if my SD card isn't beginning to fail, seeing how it was only the one shot.
It doesn't look like a sensor issue since the streaks are neither vertical nor horizontal.

It looks like an issue with the conversion from RAW which takes place when you display the photo. Is your PC's viseo card perhaps not set to display the most colors possible?

03-15-2009, 11:11 AM   #9
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I've seen that before. It was explained to me as quantization error.
03-15-2009, 02:10 PM   #10
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For me that very much looks like a screen or graphics card or file format related problem, which will only be adversely affect the image on screen. It could be an out-of-gamut effect or a compression artefact (due to its seemingly regularity).

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03-15-2009, 02:11 PM   #11
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QuoteOriginally posted by Wheatfield Quote
I've seen that before. It was explained to me as quantization error.
That's also a possibility. At least I realy think, it is not a camera issue.

Ben
03-15-2009, 02:41 PM   #12
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QuoteOriginally posted by Ben_Edict Quote
That's also a possibility. At least I realy think, it is not a camera issue.

Ben
I'm glad to hear the concensus. I wouldn't be at all suprised if it were a graphics hardware/software issue, seeing as how I was using a laptop.
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