due to the ladder-like internal structure around the sensor of some cameras, it does NOT fit on some cameras such as Olympus E-PL6, E-PL5, E-PM2, E-M5 mark I, but does fit on the E-M5 mark II
specs
25mm f/0.95
manual focus
43mm filter thread
11 blades
11 elements in 9 groups incl. 1 x ED, 4x extra high RI, and 2x high RI elements