I like to do mountain bike and rock climbing photography. Currently use GX-1 body, 42mm Pano 1.7 OIS, 20mm Pano 1.7 I know it isn't the best for fast action so I do the best I can, prefocusing, etc. Weight and size are very important as we are already hauling lots of gear. I'd like to step up to a bit better performance but want to stay around 500 or less and used. I see some GH3 around $600, am I looking in the right direction? I don't expect to get the performance of new bodies, I know PDAF is available on new models but it looks like I am priced out of those bodies. So I guess my question is, is there a $500 body that wpuld be a worthy upgrade?