This thread is for the original 'K' series Pentax 50mm f1.2 - this one has the following printed on the front: SMC Pentax 1:1.2/50 then the serial number, then ASAHI OPT. CO., JAPAN. There was a later version that is very similar optically but had an extra aperture blade (9 as opposed to 8 on the K). Printed on the front is SMC Pentax-A 1:1.2 50mm. This version is usually more expensive because of more metering functionality on Pentax dSLRs, but there shouldn't be any difference on Micro Four Thirds. I've only just got my copy, so hopefully I'll have some more shots and thoughts to share soon :smile: Here's one to start - f1.2 on GH2 with Fotodiox adapter.