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

[gladstone]

Hallo,

Du kannst zB bei Ebay mit den Schlagworten Zeiss Proxar B57 2m suchen.

https://www.ebay.de/itm/256179888335...Bk9SR5Lo4JPeYw

LG, Christian

[Contax-oldies]

Hallo,

Du kannst zB bei Ebay mit den Schlagworten Zeiss Proxar B57 2m suchen.

LG, Christian

Vielen herzlichen Dank, Christian, fuer den Link und den ganz konkreten Hinweis. Das hilft sehr.

Gilberto

[hofsethpaul]

I remain curious as to WHY changing the focal length by adding a diopter lens in front provides a cure against skewed rays through excessive glass in front of the sensor while not altering angle of view, while still allowing infinity focus. Can anyone explain ?

p.

[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.