Since most probably this will be the next lens I get for my E-PL2, I'd like your opinion on how the AF fairs on this body. I've seen videos on youtube where the 45mm was very fast on the E-P3 and new bodies in general, but much slower on something like the E-P2. I understand it's optimized for the newer cameras. Nevertheless, is a firmware update the solution? (my E-PL2 has the latest firmware installed already).