I recently bought this lens for my new Oly E-M5II camera. Its primary use is for bird photography, shorebirds on the Long Island Sound where I live and my personal friends at the backyard bird feeders. I tried this lens in the field at different combinations of aperture and shutter speed, ISO 800 to 1600. The E-M5II controls noise well up to ISO 1600 (I shoot in Raw and develop in Camera Raw or DxO Optics Pro). . A fully open lens shows visible light coming in at the edges, but a single stop takes care of that (and adds some depth of field). I can't complain about the hardness. Most of the images I see on web reviews aren't that sharp, but I find that this is often due to people not handling their files properly. I increase local contrast and overall sharpness and usually get very sharp results (printable up to 16x24 inches with no artifacts). Check out my first shot at Gl. 600mm, f/8 and 1/1000s on a tripod. I posted another one just to show what a lens can do for landscapes. I love the power, size and zoom mechanics (which also look good). People complain that longer lenses unbalance small cameras like OMD, but I disagree. Leaving the lens in your left hand right by the zoom ring gives you a very good balance, even better than holding a camera and a smaller lens. A 600mm f/5.6 for just over $500 is something to praise. I found it "like new" (and it is) a few hundred bucks less and settled for it. If you're looking for a relatively cheap telephoto lens in the M43 system, give this guy a try.