you mean youre using a non-m43 mount lens on the camera? because rokinon (samyang) has a 7.5/3.5 made for m43.

i can speak onto to that version but it is surprisingly sharp at ALL apertures. shoot it at 3.5 happily. f8 at 8mm guarantees focus throughout the entire scene, but being so short, even 3.5 and dial pegged to infinity focus everything beyond a few inches is locked in.