6x lens Modulation Transfer Function curves

[Tom Roper]

Originally Posted by A. J. deLange

No. If you set G-R to +3 that increases the amount of green sensor data that appears in the red channel. If you set R-G to the same value that increases the amount of red sensor signal which appears in the green channel. If you are photographing a red object, for example, increasing G-R doesn't do anything since the red object does not stimulate the green sensor. Increasing R-G takes some of the red sensor signal and puts it in the green channel so the object no longer looks red but red-green.

Okay. Assume I have a red apple and a green apple in the frame. What you are saying is that if I increase the R-G matrix, the red apple gets some green to it with no change to the green apple. If I increase the G-R matrix, the green apple gets some red to it with no change to the red apple.

[A. J. deLange]

Originally Posted by Tom Roper

Okay. Assume I have a red apple and a green apple in the frame. What you are saying is that if I increase the R-G matrix, the red apple gets some green to it with no change to the green apple. If I increase the G-R matrix, the green apple gets some red to it with no change to the red apple.

Yes, that's it. Which reminds me of an anecdote from the early days of color television i.e. in the testing phase, probably at the Sarnoff lab. The camera was focused on a bowl of fruit in a lab remote from the one in which the other equipment was set up. The technicians could not get the matrix set right no matter what they did (twiddled pots in those days). They could get all the fruits in the bowl looking except the banannas correct but when they did that the banannas looked blue. If they got the banannas anywhere near correct everything else was way off. Turns out, of course, that some wag had snuck back into the lab and substituted a blue bananna for the original.

[Tom Roper]

Originally Posted by A. J. deLange

Turns out, of course, that some wag had snuck back into the lab and substituted a blue bananna for the original.

Lol...

Your explanation is the best. Nice to have someone articulate it. Thanks!

BTW there is nothing wrong with kitchen chemistry as long as you're not pouring them down the drain! Out of curiosity, do you have MTFs for the various Canon XL-H1 lenses in the vertical?