I just received my first telephoto lens which I hope to use more often then the 400 mm Bis-Telar I already had. I have two questions:
1. I am not sure how to calculate bellows extension factor. I have read about the method based on magnification factor but I think it is very inconvenient. Could I just use bellows extension and use actual extension at infininty instead of focal length in my calculations?
2. It is an old lens and I am not sure of it's focal length. So the question is how to establish real FL for a tehephoto design?
Jan
Bookmarks