1954 version of the Ihagee Exakta VX (East Germany) 35 mm SLR introduced an external auto-diaphragm lens system using a spring-loaded shutter button plunger connection rod.Wade, Collector's Guide. p. 152 1958 Voigtländer Bessamatic first leaf shutter 35mm SLR with a built-in light meter coupled to a viewfinder exposure control indicator – a galvanometer needle pointer. 1959 Zeiss Ikon Contarex (West Germany): first focal-plane shutter SLR with a built-in light meter coupled to a viewfinder exposure control indicator – a galvanometer needle pointer. It had an external, circular selenium photoelectric cell mounted above the lens;Lea, pp. 282–283 earning it "Bullseye" (in USA) and "Cyclops" (in UK) nicknames. For proper exposure, the photographer would adjust the meter, which was also coupled to the shutter speed and lens aperture, until the needle was centered on a mark.Small and Barringer. pp. 73–76 (The Carl Braun Paxette Reflex [West Germany] leaf shutter SLR had an external top mounted, coupled light meter needle system in 1958.) The Contarex also had interchangeable film backs, a feature common with medium format SLRs and used in a few 35 mm rangefinder cameras, but almost exclusive to Contarex/Contaflex series among 35 mm SLRs. Although Contarex SLRs and their Zeiss lenses were of extremely high quality, they were also extremely expensive"Modern Photography's Annual Guide to 47 Top Cameras: Zeiss Contarex SE," p. 124. Modern Photography, Volume 36, Number 12; December 1972. . (Contarex SE w/55mm/1.4 Planar $1212; Leicaflex SL w/50mm f/2 Summicron-R $918, p. 111; Nikon F2 Photomic w/50mm f1.4 Nikkor-S $660, p. 117; Topcon Super D w/58mm f/1.4 Auto-Topcor $520, p. 105)Norris D. and A. Ross McWhirter, compilers, Guinness Book of World Records. 1971–1972 (10th) edition. Bantam Books, New York, 1971. "The most expensive miniature camera is the Zeiss Contarex, Pentaprism Reflex, with a built-in photo-electric meter and Zeiss Planar f/1.4 55 mm lens. With a full range of accessories, including two wide-angle and three telephoto lenses, this would cost about $4000." p. 149 and of idiosyncratic (even clumsy) handling.Matanle, pp. 93–96 1959 Nikon F (Japan): first pro caliber 35 mm system SLR,Schneider, "How The Japanese Camera Took Over." p. 78Stafford, Hillebrand & Hauschild, pp. 19–24, 267–270 first electric motor drive accessory for SLR. (The Japanese Nikon SP 35 mm rangefinder camera had the first electric motor drive for any camera type in 1957.Stafford, Hillebrand & Hauschild, pp. 13, 281–282) Well-integrated, durable and reliable focal-plane shutter, instant return mirror, pentaprism