Carl Zeiss Biogon 2.8/28 T* für Contax G an Sony Nex

[gladstone]

Hello Paul,

I am not an optics expert, but you are right that adding a positive lens will lower the focal lenght. You have to compensate that,
by lowering the Distance from the optical block to the sensor. The Contax G lenses gladly allow this.

But I have no idea, why the optical performance (field curvature) gets better in some cases...

Best regards, Christian

[hofsethpaul]

C:

Thamks for pointing this out althouhgh my confusion only increases.

A closer rearlens shiould make the edge rays even steeper increasing the risk of adjoining sensels being disturbed, and the wieving angle will cerrtainly be changed together with the focal lenght. Even though many less exact users mistakenly call this remedy a "filter" it cannot just be a pacebo effect.

p.