Rokinon 300M-M-BK 300mm F6.3 Mirror Lens for Canon M Mirrorless Interchangeable Lens Camera 300mm Mirror Lens with F6.3 Aperture Constructed of 9 elements in 9 groups Designed for mirrorless interchangeable lens cameras Minimum focusing distance 2.95 feet; angle of view 5.4 degrees on Canon M, Fuji X and Sony NEX, 4.2 degrees for MFT