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Old Jun 22, 2006, 11:39 PM   #1
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I had been passed to images to edit this week taken on a D70, at iso 200 mid day on a bright sunny afternoon. I had requested RAW but they had been shot superfine jpg. The sky appeared a little too blue and the histogram confirmed the subject was a little underexposed but nothing major. My main surprise was the noise levels in the sky, a lot of red color noise. I had thought this camera would have performed better, I guess the photographer is not fully au fait with his equipment. Any ideas what may have been set wrong, I know the guy so when he comes in for the edit i want to chat about the image and how it could be improved next time (less edit time time )
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Old Jun 23, 2006, 2:55 PM   #2
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Could some one move this to the Nikon DSLR forum please.
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Old Jun 23, 2006, 3:23 PM   #3
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Thread moved.

How underexposed was it?

If you underexpose an image and brighten it in software, visible noise will increase, just as if you used an even higher ISO speed to begin with.

Blue Skies are tough on Digital Cameras from a noise perspective.

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Old Jun 23, 2006, 5:00 PM   #4
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Not very underexposed, the histogram was fairly well balanced just a touch to the right. giving some shadows around the eyes of the subjects but the background was fine and the sky very clear and blue but noisy. I left them at work I should have copied the sky so I could post it.
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Old Jun 23, 2006, 5:45 PM   #5
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Just about any digicam (even DSLR's) will show some noise in the sky, especially when underexposed. As JimC said brightening it will make the noise even worse. You really have to work to nail exposure with digicams, as they have significantly less latitude for exposure.
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Old Jun 23, 2006, 9:18 PM   #6
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You may try to shoot in RAW vs JPEG and compare the results.

I heard that JPEG is basically a ***color-limiter*** i.e. the high-frequency changes in colors are stripped away to enable compression.

Unfortunately the sky is exactly very rich in color/brightness variation over very large areas.

So once compressed, JPEG may show "patches" of blues instead of continuously changing blues.


Just my stupid opinions
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Old Jun 24, 2006, 9:58 AM   #7
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I think that might be it BP. I have suggested we shoot in the same place again but this time get RAW. I had hoped for RAW the first time. It will be interesting to see if the noise was introduced by the jpg. Also I will take my laptop so we can analyze the images straight away so he can work on getting the exposure. Too late for the picture he needed but will be good for the future.
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