Panasonic Lumix G 20mm F1.7 II (H-H020A) - Banding

Started Aug 6, 2013 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: Panasonic Lumix G 20mm F1.7 II (H-H020A) - Banding

tsi wrote:

Anders W wrote:

tsi wrote:

I forgot that blue and red are on different rows in the bayer pattern. For some unknown reason I thought that they are mixed on the same row.

Even if blue and red were mixed on the same row, you might still see color shifts with the banding. Suppose for example, that both red and blue are significantly weaker (in RAW) than green as would be the case in a white area illuminated by daylight. If there is a positive read error for a row (or set of rows) due to the interference, it (they) will come out more magenta than average (because the error effectively boosts red and blue more than green). And if the systematic read error is negative, the row or rows will come out more green than average for the same reason.

I misunderstood before. I thought that by refering to the systemaic difference of rows you wanted to say that the symmetry of the read out would strengthen a color error. However with your last comments I understand that you just refered to the signal difference caused by the lens.

In this case, it is what I wanted to say with... "The banding is the same for all colors, but the color conversion misinterprets it as a color difference."

white balance: rgb_raw = [0.5 0.8 0.2] -> rgb = [1 1 1]

with positive read error of 0.1: rgb_raw = [0.6 0.9 0.3] -> rgb = [1.5 1.1 1.2]

OK. I too misunderstood what you meant with your first point when you first posted it. We see eye to eye on this now. Note, however, that even if the three channels were evenly balanced in RAW for a white daylight signal, you'd still see color shifts due to the banding whenever the colors happen to be (for perfectly natural reasons) of different strength. You wouldn't see it for pure white though.

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