The Heliar 75 f2.5 is very sharp on the Nex and m4/3 systems. I like using it on the E-PL1 although focusing is a little harder but the lens delivers; a little better on the m4/3 system. Or it could just be that I like the rendition better on that system. That 24MP sensor is really hard on some of these lenses. They just weren't built for this type of system and I'm thinking that the sensor out-resolves the lens.