The Leicaflex SL was an SLR made by Leitz from 1968 to 1974 as the second iteration of the Leicaflex series.
In 1968, Leitz responded to the critics of the non-TTL meter of the original Leicaflex by introducing its successor the Leicaflex SL with a TTL meter. The SL designation in the name was an abbreviation of "Selective Light", the name chosen by Leitz for its implementation of TTL metering. This system metered a limited area represented by the viewfinder's central microprism spot. At a time when SLR manufacturers were divided between those embracing TTL metering at full aperture (such as Nikon and Konica), and those with mounts which permitted only stop-down metering (such as Pentax and Canon), Leitz chose to implement full aperture metering on the Leicaflex SL.
Light measurement was by a cell mounted in the camera base pointing upwards with light directed onto it by a small secondary mirror hinged from the main mirror, the central portion of the main mirror being semi silvered. A similar arrangement was used in every successive R camera.
Leitz also addressed complaints about the original Leicaflex focusing screen in the SL focusing screen, which offered a ground-glass focusing screen with a central microprism spot. This more conventional configuration did not prevent it from being very bright and comfortable.
The Leicaflex SL replaced the mirror lock-up function of the original Leicaflex with a depth of field preview. The principal effect of this change was to obsolete the rangefinder-derived 21mm f/3.4 Schneider Super-Angulon lens which, due to the protrusion of the rear element into the camera body, was designed to work with the mirror locked up in conjunction with an external viewfinder. This lens cannot be mounted on the SL or its followers without mirror lockup. The original Leicaflex Super-Angulon was replaced by the retrofocus type 21mm f/4 Super-Angulon-R, which can be mounted in the conventional way.
The Leicaflex SL is identifiable by the letters "SL" on the front of the prism housing, which replaced the meter window and battery cover of the original Leicaflex. It was offered in chrome as well as black finish. Black SLs initially bore a black enamel finish, which was subsequently replaced by a more durable "black chrome" finish. 70,995 serial numbers were allotted to the Leicaflex SL.