Undrar om inte detta är vad som kallas hotpixels:
Citat:
quote:
Hot pixels are part of the CCD reality.
Each CCD has millions of pixels sensitive to brightness (Well you know how many, you can't miss that: 3.3 MegaPixel etc..). These pixels are on a very small space. In consumer cameras this would be from 8 mm to half an inch. (Nice mixture of measures:-)
These pixels are never the same and each of them has different charge leakage rate.
If you expose the CCD long enough, the pixels thanks to this leakage will simply lighten up even with no light. (Any photosensitive silicon material is sensitive to charge as well)
Because of different quality and sensitivity of each pixel, they will start appearing as a noise - but if you would able to expose for much longer, finally all pixels will lighten up.
Many consumer digital cameras don't have longer exposure times - and this is because of Hot Pixels (80% of people would think that the CCD is defective). Today CCD's are reasonable up to 1-2 sec of exposure. (It depends on a temperature as well - remember, more heat, the electrons are vibrating faster - more of them will escape from wherever they are - more charge leakage)
But the cameras which allow for longer exposures will always have this problem.
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Det finns till och med ett gratis verktyg som tar bort dom:
http://www.mediachance.com/digicam/hotpixels.htm
(Det är fö därifrån citatet ovan kommer ifrån)
/Mats
