India
India
The Electromagnetic Diaphragm (EMD) is designed to work in tandem with the fully electronic lens mount system to provide high-precision digital aperture control. The EMD combines an aperture-blade unit and a deformable stepping motor. Compared to the system used in conventional cameras, where the aperture blades are opened and closed by mechanical levers in the camera, the new system is able to provide much higher precision control. The aperture can be controlled using an electronic dial on the EOS body, or using an electric pulse signal to set the calculated aperture value. Since no levers are involved, operation is smooth. The introduction of EMD also led to the creation of some very unique lenses, including the world’s first* TS-E lens with automatic diaphragm — an innovative and widely praised lens developed in 1991. In 2021, Canon developed the RF5.2mm f/2.8L DUAL FISHEYE lens, Canon’s first Stereoscopic 3D 180° VR lens equipped with two 5.2mm fisheye lenses. Both the right and left lenses feature separate, synchronized EMDs. Electronic signals can thus control the two EMDs simultaneously, to set the same exposure for both the left and right lenses for easy exposure adjustments.
*Refers to SLR cameras equipped with both tilt and shift functions (as of April 1991)
