An interesting article by Roger Ciala and Brian Caldwell

[ErikKaffehr]

Hi,

This article is worth reading for anyone making use of legacy lenses on new cameras:

http://www.lensrentals.com/blog/2014/06/sensor-stack-thickness-when-does-it-matter

What the article says that the optical package in front of the sensor affects sharpness if exit pupil distance is short. The article lists thicknesses for the cover glass/optical package for different system and also exit pupil distance.

So this explains some issues with legacy lenses on modern cameras. It also explains why Leica made the lens cover glass/IR filter very thin on the M-series.

Modern lenses designs probably take the cover glass into account.

This article goes a bit deeper: http://www.lensrentals.com/blog/2014/06/the-glass-in-the-path-sensor-stacks-and-adapted-lenses

Best regards
Erik