A mirrorless camera is a digital camera which, in contrast to DSLRs, does not use a mirror in order to ensure that the image presented to the photographer through the viewfinder is identical to that taken by the camera. They have come to replace DSLRs, which have historically dominated interchangeable lens cameras. Other terms include electronic viewfinder interchangeable lens (EVIL) cameras and compact system cameras (CSCs).

The E-mount is a lens mount designed by Sony for their NEX and ILCE series of camcorders and mirrorless cameras. The E-mount supplements Sony's α mount, allowing the company to develop more compact imaging devices while maintaining compatibility with 35mm sensors. E-mount achieves this by:Minimising mechanical complexity, removing mechanical aperture and focus drive. Shortening the flange focal distance to 18 mm compared with earlier offerings from Sony which used 44.5 mm. Reducing the radius of the flange.