I got to wondering, so I used black gaffers' tape to mount a couple of M lenses on a Canon 10D. The mirror box allows the lens to snug right in and avoid the mirror itself. WOW !!!!! The best Macro shots I've taken outside of my Contax 120/4 mounted to a 645. Incredibly sharp, crisp images with wonderful color and tonal rendering. Used a 50 Lux and then a 90AA. The 90 allows you to get further away. Next I'll try the 135/3.5. Okay, who is an engineer here? We need a simple adapter to do this and those with a digital camera will have the best macros they've ever used on a digital camera. Lutz, you there? Something you can get done?