Process lens image circle nature

[Pere Casals]

I am planning to buy my first large process lens and I am wondering how does various process lenses image circle behave. Is it quick cut off or more gradual fade?

I am considering something around 750-800mm range and I plan to use it for portraiture (i.e. 1:1).

My LOMO O-2 600mm, a dyalite type, covers 41º in the specs but it illuminates around 90º, with increasing softness when going beyond the specified coverage circle.

Illumination circle of APO-Nikkors are also reportedly very big: https://www.largeformatphotography.i...ll=1#post56941

So for your application they may work, as you may have the corners in the out of focus, still you will have fall-off in the outer illumination boundary.