Canon A-1 - Features

Features

The A-1 accepts any lens with the Canon FD breech lock mount (introduced in 1971) or Canon New FD pseudo-bayonet mount (sometimes called the FDn mount, introduced 1979). This excludes all of Canon's EF bayonet mount autofocus lenses (introduced in 1987). During the late 1970s and 1980s, there were approximately 55 Canon FD lenses available for purchase. They ranged from a 7.5mm f/5.6 fisheye to an FD 800mm f/5.6 telephoto, and included lenses with maximum apertures to f/1.2 and a line of L-series lenses of exceptional quality. Accessories for the A-1 included the Canon motor drive MA (automatic film advance up to 5 frames per second), the Canon Databack A (sequential numbering or date stamping on the film), and the Canon Speedlight 155A (guide number 56/17 (feet/meters) at ASA/ISO 100) and Canon Speedlight 199A (guide number 98/30 (feet/meters) at ASA/ISO 100) electronic flashes.

The A-1 is a battery powered (one 4LR44 or PX-28) microprocessor controlled manual focus SLR with manual exposure control or shutter priority, aperture priority or programmed autoexposure. A fifth mode is "stopped down AE", in which the aperture is closed and alterable by the photographer and the camera selects the shutter speed based on the actual light reading. This differs from aperture priority in which the aperture is not closed until a photograph is taken and the shutter speed is calculated based on the light measured through the fully open aperture. Stopped down AE is therefore useful if there are concerns about depth of field and focus or accuracy of exposure. It is the first SLR to have all four of the now standard PASM exposure modes. It has a viewfinder exposure information system using a six digit, seven segment per digit, red alphanumeric LED display on the bottom of the viewfinder to indicate the readings of the built-in centerweighted, silicon photocell light meter. The focusing screen also has Canon's standard split image rangefinder and microprism collar focusing help.