The K1000 was an almost all metal, mechanically (springs, gears, levers) controlled, manual-focus SLR with manual exposure control. It was completely operable without batteries. It only needed batteries (one A76 or S76, or LR44 or SR44) for the light metering information system. This consisted of a center-the-needle exposure control system using a galvanometer needle pointer moving between vertically arranged +/– over/underexposure markers at the right side of the viewfinder to indicate the readings of the built-in full-scene averaging, cadmium sulfide (CdS) light meter versus the actual camera settings. The meter did not have a true on/off switch and that the lens cap needed to be kept on the lens to prevent draining the battery when the K1000 was not in use. The viewfinder also had a focusing screen with a microprism spot focusing aid. The Pentax K1000 SE substituted a split image rangefinder plus microprism collar focusing screen. The K1000 SE is otherwise identical to the regular K1000, except that the SEs from the first few years of production used brown leather instead of black. The K1000 was often sold with a version of the SMC Pentax 50 mm f/2 lens. However, as an interchangeable lens camera, the photographer could dismount and exchange its lens for another. The K1000 accepted all manual focus lenses with the Pentax K bayonet mount, introduced in 1975 with the Pentax K-series SLRs. This included the K-A mount lenses introduced in 1983. The contemporary Asahi Optical made manual focus lenses were the SMC Pentax, SMC Pentax-M and SMC Pentax-A types. In addition, almost all lenses with the Pentax K-AF and K-AF2 autofocus lens mounts (introduced 1987 and 1991, respectively) would also work; for manual focus, of course. The exceptions are Pentax's newest SMC-Pentax FA J (1997) and SMC-Pentax DA (2004) types lacking an aperture control ring. They will mount on the K1000, but have severely restricted functionality. Asahi Optical used to sell the Mount Adapter K to allow their older Takumar screw mount lenses (see below) to be used on K mount cameras (with severe limitations), but it is now a collector's item. In 2006, Pentax said that it had manufactured more than 24 million lenses over fifty years that could provide at least some functionality on the K1000. The number of independent manufacturer Pentax-compatible lenses is also huge, but indeterminate. Except for taking the enormous variety of lenses with the popular K mount, the K1000 had very few other features compared to higher level SLRs of mid 1970s. It had a slow top flash synchronization speed of 1/60th second, cheaper, sleeve-bushing equipped shutter and film advance mechanisms, no self timer, no depth-of-field preview, no mirror lockup, no interchangeable focusing screens, no motor drive option, and most emphatically, no autoexposure. The K1000 did not even have a film box end memo holder! The K1000 did accept any nondedicated hot shoe mounted or PC terminal X-sync electronic flash for guide number manual or flash mounted sensor automatic exposure control. The venerable Vivitar 283 (guide number 120,