Pentax Spotmatic

The Pentax Spotmatic is a range of 35mm single-lens reflex cameras manufactured by the Asahi Optical Co. Ltd., later known as Pentax Corporation, between 1964 and 1976. The original 1964 Spotmatic was one of the first SLRs on the market to offer a through-the-lens (TTL) exposure metering system. The camera had originally been designed to use spot metering, and this feature was included in prototype models exhibited at Photokina 1960. Shortly before production Asahi decided that spot metering would be too difficult to use, and so the metering system was altered to use average metering, and with later models a center-weighted system. The change took place too close to production to change the name, and so Spotmatic stuck.

The model range includes the original Spotmatic, Spotmatic II and IIa, Spotmatic F, plus the SP500 and SP1000. There was also the Pentax SL, which was identical to the Spotmatic except that it did not have the built-in light meter. In 1971 the Electro-Spotmatic was the first aperture-priority, electronic, automatic SLR and was sold as a trial only in Japan. It was followed by the ES sold internationally in 1972. Two years later it was followed by the ES II. The ES had standardized and improved circuity that addressed reliability issues in the original version.

All Pentax Spotmatics use the M42 screw-thread lens mount. The lenses are focused at maximum aperture to give a bright viewfinder image for focusing, then a switch at the side stops the lens down and switches on the metering to enable the exposure to be set prior to shutter release. The Spotmatic F, Electro Spotmatic, ES, and ESII models are capable of open-aperture metering when used with lens models which support this feature.

Honeywell was the U.S. importer of the Spotmatic. Cameras officially imported by Honeywell were labeled Honeywell Pentax, instead of Asahi Pentax. The Spotmatic IIa was only available as a Honeywell Pentax; it was sold exclusively in the USA and had an electronic interface for specific Honeywell Strobonar electronic flash units.

All Pentax Spotmatics made use of Takumar lenses. These were high-quality, progressively improved lenses made by Asahi Optical Co. Ltd., later versions of which featured multi-coating. The cameras were also compatible with other M42 screw mount lenses.

The Pentax Spotmatic chassis was the basis for the Pentax KX, KM and K1000 models with Pentax-K bayonet mounts.