Can someone explain the purpose of custom function I 13 to me? It has something to do with setting the minimum and maximum apertures and goes from f1 to f91. I've never seen f91 except on LF. Even with f32 and a 2x multiplier the aperture only goes to f64.
Also, function I-12 has something to do with the shutter speeds and I do not know when that is used. The manual describes how to change the setting but not what it is used for.
Thanks for your help.