Some notable specs: Length: 195mm / 7.67 inches long Weight: 1190 grams / 2.62 pounds Takes a 77mm filter 1.2m / 3.93 feet minimum focus 1:3 reproduction ratio Compared to all the other 300mm lenses I have used in the past: Panasonic 100-300 Olympus 75-300 II Tamron 70-300 SP VC Canon FDn 80-200 F4 L + 2XB Teleconverter This lens is sharper than all the above @ 300mm. And with focus peaking on the E-M1 it is a breeze to use. Build quality is outstanding. Only downside is weight. Here is one I shot today. Processed in Darktable, Gimp, and Darktable.