the olympus is the only lens a zenmeuse will fly hence it's popularity.... I've seen a few hacks that make that an even better lens especialy in the dark, my only gripe with it is it's lens flares are less than awesome and if your shooting for cinematography it's a swing and a miss.... the rokinon, voigtlander and heck, even panasonic make some pretty cool flares, have great dynamic range results looking at sun and still seeing objects of interest very very well. My favorite is the rokinon line mainly for it's glass and oversized aps-c format gives super sharp pictures out and beyond the edges. The voigtlander speed is insane and somewhat hard to tame in the day, takes alot of nd but man you turn that thing on at night with no filters and it's almost like color night vision, it's truly impressive if you got the rig to fly 2-3lb lenses. It's aluminum frame takes a lickin and keeps on tickin.... mines fell 30', bounced back up 50' with my cameras lens mount in tow and never blinked,,,,, still fly it today
Theres a bunch of cheaper chineese glass coming out that kinda has my attention but i'm not expecting a whole lot once you see something done with japanese glass
if you get a metabones the canon lenses are almost impossible to pass up