Hang on... where did you get a 300mm lens from? Would I be correct in guessing that it's the 75-300 f/4.8-6.7 Mk II, based on me seeing a shot earlier that was at something like 210mm? The new f/4 IS Pro was released well after these shots and is a prime, so it can't be that. (And almost 3 and a half grand in AUD.) Mind you that's not as bad as the Zuiko (standard 4/3) f/2.8, which comes in at almost 9 grand AUD, but it's also a prime.
