To use the camera as an extension of the body: because every photographer shares this desire, Canon adopted a revolutionary fully electronic lens mount that eliminates all mechanical links between the lens and the camera. With the electronic mount, all data transfer between the EF lens and the camera body is electronic. Autofocus communication links between the lens and the body are maintained, even when an extender is used, ensuring optimum operability and durability in even the most severe conditions. Canon’s large, 54mm diameter electronic lens mount facilitated the design and production of the EF50mm f/1.0L USM, the world’s fastest 35mm SLR camera lens.
With the ability to produce fine detail and attractive background blur even in candlelight, this large-aperture lens expanded the domain of photographic expression. A large-diameter electronic lens mount also paves the way for future system upgrades and further advances in lens design, such as large-aperture prime lenses and high-power zoom lenses.