SLR Autofocus

The first autofocus 35 mm SLR was the Pentax ME-F released in 1981.^[6]
The Minolta Maxxum 7000, released in 1985, was the first 35 mm SLR with integrated autofocus and motorized film-advance winder, which became the standard configuration for SLR cameras from then on. This development had significant impact on the photographic industry.
Some manufacturers discarded their existing lens systems to compete with other manufacturer's autofocus capability in their new cameras. This was the case for Canon, with its new EOS lens line. Other manufacturers chose to adapt their existing lens systems for autofocus capability, as was the case with Nikon and Pentax. This allowed photographers to continue using their existing lenses, which greatly reduced the cost of upgrading. For example, almost all Nikon lenses from the 1960s and later still function on the current Nikon bodies, only lacking autofocus. Still some manufacturers, notably Leica with its R-system lenses, and Contax with its Zeiss lenses, decided to keep their lens mounts non-autofocus.

Typical film SLR viewfinder information

From the late 1980s competition and technical innovations made 35 mm camera systems more versatile and sophisticated by adding more advanced light metering capabilities such as spot-metering; limited area metering such as used by Canon with the F1 series; matrix metering as used by Nikon, exposure communication with dedicated electronic flash units. The user interface also changed on many cameras, replacing meter needle displays that were galvanometer-based and thereby fragile, with light-emitting diodes (LEDs) and then with more comprehensive liquid crystal displays (LCDs) both in the SLR viewfinder and externally on the cameras' top plate using an LCD screen. Wheels and buttons replaced the shutter dial on the camera and the aperture ring on the lens on many models, although some photographers still prefer shutter dials and aperture rings. Some manufacturers introduced image stabilization on certain lenses to combat camera shake and to allow longer hand-held exposures without using a tripod. This feature is especially useful with long telephoto lenses.