[marknorton]

Scott, certainly very interesting. I especially like the way you are plotting R relative to B+G to normalise for the overall sensor vignetting correction.

If I understand you correctly, these shots are with IR filters and show that the M8 already has some correction for red vignetting which is effective in that the corrected results for both lenses are the same. The residual fall off is then caused by the IR filter which is largely independent of both lens type and aperture.

It would be interesting to know how close to flat the results are without an IR filter. I agree with you the lens recognition menu will need to specify whether or not an IR filter is used and so allow additional correction. Still an open question whether different makes of filter cause different levels of vignetting.

I'm wondering whether there is at least some correction applied even if lens recognition is turned off?

The whole lens coding idea is at last being shown to be delivering value - no thanks to Leica who are altogether too vague about detailed technicalities.

Interesting piece of work, thank you.