If you seek an ultra-wide in M-mount, it doesn’t get any wider than this. Like stated above, you do have some corner color shift to contend with, especially on the M9. I wouldn’t let this be an eliminating factor, as this lens is one-of-a-kind. It’s rangefinder-coupled for nearly the whole focus range, but you can pretty much guesstimate distance and you’ll have pretty good focus.

Since the M-mount lenses aren’t used on just M-mount cameras anymore, I did test the Voigt 12mm on our mirrorless cameras via adapters. It does surprisingly well on the Sony NEX-5n, even slightly better than the M9! Next up was the Ricoh GXR, which again, performed beautifully. Lastly, I’d tried it on a couple micro 4/3rds cameras, which was quite a disappointment. There was some pretty bad corner smearing at f5.6, and stopping down didn’t really clear it up enough to say it’s worth using. Therefore, we’d say opt for one of the native micro 4/3rd’s mount wide angles if needed. One thing to note, despite all three of the mirrorless mount’s crop factors, the corner color shift was still visible.