Inspired by a post on MU-43.com I've brought a 50mm f/1.2 projector lens & mounted it in an old helicoid. For the princely sum of $10 (+ postage) & a few hours in the workshop I now have a working f/1.2 :-)
frankenlens 1 by Mike Kanssen, on Flickr
The rear of the lens tube had to be removed to...