The E-mount is a lens mount designed by Sony for their NEX ("New E-mount eXperience") and ILCE series of camcorders and mirrorless cameras. The E-mount supplements Sony's A-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.
The short flange focal distance prohibits the use of an optical viewfinder, as a mirror box mechanism cannot be included in this reduced distance. Therefore all E-mount cameras use an electronic viewfinder.