Comen, Nikon Classic Cameras; F, FE, FE2, FA and Nikkormat F series. First Edition. Magic Lantern Guides. Rochester, NY: Silver Pixel Press, 1996. . pp. 63–85 all from Japan) made the Japanese 35 mm SLR the dominant advanced amateur camera by the late 1960s. 1964 Krasnogorsky Mekhanichesky Zavod (KMZ) Zenit 5 (Soviet Union; Зенит 5): first SLR with built-in electric motor drive. Had a Ni-Cd battery powered motor for automatic single-frame film advance with a backup film wind knob. In 1970, the Minolta SRM (Japan) was the first SLR with built-in electric sequential motor drive and first SLR with auto film-rewind. It was a modified Minolta SRT101 with a permanently bottom-mounted motor drive (eight AA [LR6] batteries) and detachable handgrip for continuous three frames per second sequence shooting, but no light meter.Hansen and Dierdorff, p. 99 Built-in motor drives did not become common in 35 mm SLRs until the mid-1980s when high-powered, energy efficient "coreless" micro-motors were perfected, but accessory drives or autowinders taking four to twelve AA (LR6) batteries were very popular in the 1970s."Modern Tests: [Konica] Autoreflex T4: The Best of Two Worlds," pp. 110–112. Modern Photography, Volume 43, Number 2; February 1979. . p. 110 This is, of course, a non-issue in modern digital SLRs. 1964 Kodak Retina Reflex IV (USA/West Germany): first SLR with standard ISO hot shoe atop the pentaprism housing for direct flash mounting and synchronization. Was a 35 mm, leaf shutter design. A flash is a necessary accessory for auxiliary or fill light in dim or high contrast conditions. The first camera with any kind of hot shoe connector was the Univex Mercury (USA) non-SLR half frame 35 mm in 1938 and many post World War 2 non-SLRs (such as the Bell & Howell Foton [1948, USA] 35 mm rangefinderJason Schneider. Jason Schneider on Camera Collecting: A fully illustrated handbook of articles originally published in MODERN PHOTOGRAPHY. Second Printing 1980. Des Moines, IA: Wallace-Homestead Book Co., 1978. . pp. 153–155) had a Leica-type accessory shoe with added electrical contact (the present day ISO hot shoe). Although the Nikon F (see above) had a non-ISO hot shoe surrounding the film rewind crank in 1959, most 1960s 35 mm SLRs used screw-on accessory shoes attached to the eyepiece to mount flashes but a PC cable socket to sync them.Herbert Keppler, "Inside Straight: Shoe Fetish: An unsung camera feature that's almost as old as the camera