of 1964) 35 mm SLR with successful shutter-priority automation (first with a focal-plane shutter). The camera also had the rare ability to allow selection between frame sizes (horizontal 24×36 mm or vertical 18×24 mm) between frames on the same roll of film. The camera used a mechanical "trap-needle" autoexposure system controlled by an external CdS meter that read light directly (not through-the-lens).Lea, pp. 122–123Lothrop & Schneider "Deutschland discoveries," pp. 67–68 1967 Zeiss Ikon Contaflex 126 (West Germany): first Kodapak Instamatic 126 cartridge film SLR. Was a Voigtländer focal-plane shutter design unrelated to 35 mm Contaflexes (see above), accepting fully interchangeable lenses.David Francis, "Contaflex 126," retrieved 10 March 2008 Took up to twenty exposures of 28×28 mm frames on paper-backed, singly perforated, 35 mm wide film pre-threaded into double-ended cartridge with film supply and take-up spools.Herbert Keppler, "New 35mm Film Format: Bogeyman Or Blessing? Kodak's teamed up with four Japanese companies for a new 35mm film system. Will it blow your present camera and lenses into the weeds of photo history?" pp. 46–49. Popular Photography, Volume 57 Number 11; November 1993. Drop-in loading 126 film was introduced by Kodak in 1963, solving the problem of amateurs' difficulty in loading 135 film manually. The 126 cartridge was an extremely popular non-SLR snapshot format for more than a decade, but began to fall victim to the increasing popularity of the 110 format throughout the 1970's.Schneider, Keppler and Lothrop, pp. 58–61 1968 Konica Autoreflex T (Japan): first SLR with internal open aperture TTL metering autoexposure (mechanical shutter-priority).Lothrop & Schneider. "The SLR Saga (part 2)," p. 64 Was an improved Konica AutoReflex (see above) with internal CdS centerweighted light meter and reduced shutter button travel, but without half frame capability.Matanle, pp. 164–165 1968 OP Fisheye-Nikkor 10mm f/5.6 (Japan): first SLR lens with aspherical elements. Was a 180° orthographic projection fisheye lens for Nikon and Nikkormat 35 mm SLRs. Typical lens elements have spherically curved surfaces. However, this causes off-axis light to be focused closer to the lens than axial rays (spherical aberration) and degrading image sharpness;Kingslake, p. 322Peres, pp. 176, 716Stroebel and Zakia, p. 840 especially severe in very wide angle or aperture lenses. This can be prevented by using elements with convoluted aspheric curves. Although this was understood since the 17th century, the grinding of aspheric glass surfaces was extremely difficultRay, pp. 50–51, 110–111 and prevented their consumer use until the E. Leitz 50mm