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Old 18-04-2011, 07:51 AM
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gregbradley
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I don't think that's right Humi. I think its the number of hot pixels that group together. There should still be zero column defects.
Its my understanding that a column defect is a more serious error that can only be fixed by a map of the chip that you use when callibrating your images. The standard for class 1 is defined on the Kodak Sensor Solutions site I am pretty sure. It has to do with only so many hot pixels in a group (6 or 8 as I recall). More than that then it becomes class 2. There is also engineering grade which is lower again. Class 2 is fine for imaging.

The KAF11002 chip (as can others in the KAF family) develop a hot pixel which because of the readout process where the lines are read and then moved down to the line below, causes the hot pixel to drag a white line down the image. This isn't though a defective column.

These lines fade with cooling. By the time you get to -35C they get quite faint. They can be a bugger in processing though.

Class 2 is fine. Darks just need to be accurate (they do anyway).
I had a class 2 and it must have just fallen into class 2 category as it wasn't that bad at all.

Greg.
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