series SLRs. 1975 Olympus OM-2 (Japan): first SLR with TTL, off-the-film (OTF) flash autoexposure. Had two rearward-facing silicon photodiodes in the mirror box to meter light reflecting off the film. Circuitry could detect when enough light was exposed and automatically quench a specially "dedicated" accessory Olympus Quick Auto 310 electronic flash."Annual Guide: 46 Top Cameras: Olympus OM-2," p. 117. Modern Photography, Volume 42, Number 12; December 1978. Hans van Veluwen, "Quick Auto 300/310" retrieved 25 September 2007 Manual flash exposure control for a natural look is complex and convenient TTL autoflash metering became standard in virtually all SLRs by the mid-1980s. 1976 Canon AE-1 (Japan): first SLR with microprocessor electronics. Well-integrated and compact shutter-priority autoexposure design with excellent interchangeable lenses and large accessory system.Francke, pp. 12–25 Backed by a major advertising campaign, including celebrity endorsements, TV commercials and a catchy slogan ("So advanced, it's simple."),"Modern Tests: Aperture-Preferred Canon AV-1 SLR," pp. 96–98. Modern Photography, Volume 43, Number 8; August 1979. that targeted snapshooters, the AE-1 sold five million units and immediately made the 35 mm SLR an important mass-market camera."Modern Tests: Canon AE-1 Program: Upgrading a Legend," pp. 112–114, 116, 118, 120, 122. Modern Photography, Volume 45, Number 8; August 1981. An improved model, the Canon AE-1 Program (Japan) of 1981, added another four million units to the tally. 1976 Asahi Pentax ME (Japan): first autoexposure-only SLR. Had aperture-priority exposure control only (photographer could not manually select a shutter speed) for simple snapshooter operation.Cecchi, pp. 103–106, 134–137Norman Goldberg, Michele A. Frank and Leif Ericksenn, "Lab Report: Pentax ME," pp. 126–129, 145–147, 212. Popular Photography, Volume 85, Number 3; March 1978. Interchangeable lens autoexposure-only SLRs disappeared in the mid-1980s, because even snapshooters demanded that SLRs (as "good cameras") have a manual mode. However, most recent amateurs never use manual control and even some professionals depend on autoexposure, making the great majority of modern SLRs de facto autoexposure-only cameras. 1976 Minolta 110 Zoom SLR (Japan): first Pocket Instamatic 110 cartridge film SLR. Had built-in zoom lens (fixed 25–50mm f/4.5 Zoom Rokkor-Macro).Keppler, "New 35mm Film Format." pp. 46–49 Took up to 24 exposures of 13×17 mm frames on paper-backed, singly perforated, 16 mm wide film pre-threaded into double-ended cartridge with film supply and take-up spools. Compact, drop-in loading 110 film was introduced by Kodak in 1972. It was briefly an extremely popular non-SLR snapshot format but almost dead by 1982. 1977 Fujica AZ-1