D7200 HPS (hot pixel suppression) news

Started Dec 8, 2015 | Discussions thread
OP Bernard Delley Senior Member • Posts: 2,176
Re: D7200 HPS (hot pixel suppression) news
2

bolador wrote:

With being "better" do you mean "not as bad"?

Or is this better to nothing..
As I suspect this kind of intervention to the data is not any good to astro photography. When a stack of dark frames should do a better job...

hot pixels are very bright, even the Poisson noise from the hot part is likely to completely mask any low light detail still recorded on such a pixel.  Also a good stack of dark cannot do away with it, it only may give an improved average value for the hot pixel. See plot 1 in my OP post for illustration. So some image cleanup has to be done for these singular bad  pixels.

Practically no lens is capable producing a star image where a single (4 micron) pixel is X  times brighter than any of its neighbor pixels. The HPS of D4 D800 D7100  allows X= 2 times brighter, and that pretty much  cuts it, even for the sharpest lenses at their optimum aperture.  The new algorithm lets X= 6-8 times brighter pixels pass, anticipating incredibly sharp lenses: this implies MTF > 80% at 125 lp/mm .   As this HPS remains very effective in removing bad pixel data, it is really a very gad algorithm.  -- I agree with you that there is a minor gripe that one would like an option to turn it off altogether.  After having seen perhaps hundreds of false stars, I might turn it on again right away

As the hot pixels tend to be permanent, there is also user controlled hot pixel remapping . Contrary to the earlier models, it is activated by a single "clean sensor now" activation on the D7200.

 Bernard Delley's gear list:Bernard Delley's gear list
Olympus TG-6 Nikon D7200 Nikon D500 Nikon D850 Nikon Z7 II +20 more
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