Quote Originally Posted by Joachim_I View Post
Does anyone know the optimal aperture of the M-Componon 80mm? I used f11 for my first attempts but plan to play around with this in future.
f/11 may well be optimal, though the with macro there are [at least] two things that may override conventional wisdom: (1) for want of DOF, you may need to stop down considerably past the 'optimal' aperture; (2) at close focus, the corner sharpness can degrade quickly... hence floating element lenses and the process lenses optimized for 1:1. Without floating elements, if you need best corner performance then sometimes you are forced to stop down in a way that degrades centre performance (via diffraction)... but at least then you have consistent performance across the frame.

Bottom line, as always: if you like your results, then keeping doing what you're doing and be happy! Nevertheless, some quick testing can give additional confidence.

P.S. the bellows factor formula I use is (1+m)^2, where m= magnification. E.g. for 1:1, m=1 and you need (1+1)^2 = 4 times longer exposure... or two stops.