Stuck pixels on my new GH2?

Started Dec 11, 2011 | Discussions thread
David Fell
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Re: Stuck pixels on my new GH2?
In reply to Brian Short, Dec 11, 2011

Brian Short wrote:

I was pixel peeping at some low light RAW pics I took tonight, at ISO 1600 and higher with the 20mm 1.7. I noticed a handful of bright green pixels throughout the images, all in the same spot from photo to photo. They don't show up in jpeg. Is this something that should be expected, or should I try to contact Panasonic?

I recall on the menu there is a tool to remap the sensor for pixel defects (GF1) but don't know whether this works on the RAW files or just jpegs, it may clear the problem. I suspect it won't as the RAW file has no processing on the data - it is what it is, and the jpegs are tweaked in the camera to negate lens and other abberations.

The likelyhood of a camera sensor (or LCD TV, Monitor) having 100% good pixels is small and there are industry standards to quantify these - to ensure a reasonable compromise on percieved quality and manufacturing yields, from what you say, I think yours is probably a typical product, i.e. not a 'reject' but in-spec. Moreover as you go up in ISO these defects get more evident as the way a sensor works is:

A pixel has photosites typically 4 (2 green, 1 red and 1 blue) and to get a higher ISO the volume is turned up on the amplifiers from these sites - noise, defects and picture data - now if there are 2 green pixels, the statistics are in favour of these being more likely to have defects. Which is what you are seeing. http://en.wikipedia.org/wiki/Bayer_filter

Hope it helps, David

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