I have the Olympus 40-150 m4/3 lens. It is the "ED MSC" version. I am pretty sure that I read that the R version of the lens is optically identical to the earlier version. My question is how is the AF speed on the newer bodies - I have the EM10 - compared to my version. Because at times the 40-150 that I have - especially at the long end - seems to take a long time (relatively speaking compared to the 14-42IIR, 14-42EZ Pancake and 17mm/1.8) to achieve AF.