Role of sensor in color rendering?

Started 3 months ago | Discussions thread
Iliah Borg Forum Pro • Posts: 27,410
Re: done!
3

Erik Kaffehr wrote:

I was thinking about linear vs. log scale

Second, measurement of small responses that are too close to read noise is not a good tactics. Neither is increasing exposure time past 0.5 .. 2 secs. We are left with light intensity control (preferred) and stacking to measure small responses reliably. If the proposed methods are not taking care of this detail IMO no reason to trust the results.

Would be interesting some of the data you measured.

That's commercial work, sorry, can't publish. Maybe next year.

One thing that surprises me in the spectral response plots I have seen is the sharp rise of the red channel around 570 nm. The drop off on the right side I would think comes from IR filter.

~570 nm is usually about the maximum roughly for the same reason photopic curve has the maximum in that area ("green", 555 nm). It is rather essential to have good response there to allow for mapping into distinctly separate tints and lightnesses.

IR filters are a bit of know-how, but the result is very close to using a BG38 (Canon) .. BG40 (Nikon) 2mm absorbing filters combined with a dichroic visible bandpass filter (say, as the coating on the dust shaker, while the dust shaker may also function as the first low pass filter) with a transmission like this:

VisiMax Thin Films

Up to 3 filters can be used to control IR and UV. For Canon, see also "phaser layer Infrared-absorption glass"

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