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07-26-2010, 03:52 PM   #1
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Long Exposure Help

Here's a test shot with a K20, 28mm, f1.7, ISO100, for about 25 minutes. At the 100% crop I've highlighed 3 common defects throughout the image. I'm guessing the dark spot is a dead pixel, the white one a hot pixel, and maybe the other is dust on the sensor? I used powerpoint to add the circles and that lost some image quality.

What's the best way to deal with the defects? Manually edit them? Does the pixel mapping feature in the camera do anything for this?

Thanks for any help...

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07-26-2010, 03:55 PM   #2
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Just clone them out. Fast & easy.
07-27-2010, 07:18 PM   #3
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Any digital sensor will produce noise during long exposures, more or less.
The DFS (Pentax calls it Long Exposure Noise Reduction) is meant to counteract that, but it won't clean it up completely.

You should do pixel mapping only if the hot/stuck pixels appear consistently at normal hand-held exposure times.
Otherwise there's no real issue.
07-29-2010, 01:50 PM   #4
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Actually until you pointed them out I didnt' even notice them on the first photo so I might just leave them if they are that small. Photography isn't perfect, when we used film we had grain that we had to live with. Now there are digital quarks that show up in small amount. For me something that small would be well within the range of things I could live with, if not use photoshop clone tool and their gone.

07-29-2010, 04:48 PM   #5
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Really. I can see the stuck pixel in the first photo (along with a second one), but that's it. Can't see the other two you pointed out at all.

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