Log in

[Robert Feldman (Rafeldman)]

I have been trying to adapt a CZJ 3.25cm f2.8  Tessar from a Robot camera for use on an Olympus Pen FT. The film-to-flange distance of the Pen is 28.95mm and that of the Robot is 31mm, so there is some room for an adapter. However, at 31mm, the rear

[Peter Robinson (Monopix)]

In principle, yes. Whether -2 is the correct strength I don't know. And whether an eyepiece lens would be good enough I'm not sure. Sounds like something you would need to try in practice.

[Rick_oleson (Rick_oleson)]

I can check your math on it if you like. Beware of optical quality in the result though, 2 diopters is a powerful lens. I did this once with a 400mm lens to convert it for medium format? went to a local eyeglass shop and got an uncut -1/4 dope eyeglass

[Robert Feldman (Rafeldman)]

Thanks for the replies.
 
I understand that what I want to do will take a bit of trial and error.
 
Two more questions:
 
1. Does the distance from the front element to the diopter lens matter?
 
2. Will using a minus diopter lens chan

[Peter Robinson (Monopix)]

1. Yes in as much the diopter lens needs to cover the full field of view of the main lens. If you move it too far, it may not fully cover the field of view. I don't think it makes any difference to the effect though.
2. It won't, in itself, c

[Rick_oleson (Rick_oleson)]

The negative diopter will slightly widen the view, but extending the lens forward slightly narrows it, so that?s about a wash. Mount the diopter as close to the lens as you can