Pentax Spotmatic

Asahi Pentax Spotmatic
Overview
MakerAsahi Optical Co
TypeSLR
Released1964
Lens
Lens mountM42 screw mount
Sensor/medium
Sensor typefilm
Sensor size24 x 36 mm
Film format35 mm
Film speed20 - 1600
Film speed detectionNo
Focusing
FocusManual focus
Exposure/metering
ExposureManual exposure
Exposure meteringAverage, through the lens (TTL)
Flash
FlashFP or X
Flash synchronization1/60
Shutter
ShutterMechanical
Shutter speed range1000 - 1 , B
Viewfinder
Viewfinderpentaprism eye-level viewfinder with a microprism focusing screen
General
BatteryEarlier model (SP) use RM400 battery; later models use PX625, but 1.5 V silver oxide batteries can be used due to bridge circuit
Made inJapan

The Pentax Spotmatic refers to a family of 35mm single-lens reflex cameras manufactured by the Asahi Optical Co. Ltd., later known as Pentax Corporation, between 1964 and 1976.

All Pentax Spotmatics used the M42 screw-thread lens mount which was developed after World War II by Zeiss and Praktica. Asahi Optical used the name Takumar for their lenses. These were high-quality, progressively improved lenses, later versions of which featured multi-coating and were called Super Multi Coated Takumars.

The camera used Through The Lens (TTL) light metering, originally it was supposed to be a Spot meter but it ended up being a center-weighted meter. This camera allowed one to focus the lens at maximum aperture with a bright viewfinder image. After focusing, a switch on the side of the lens mount stopped the lens down and switched on the metering which the camera displayed with a needle located on the side of the viewfinder. The use of stop-down light metering was at the time revolutionary, but it limited the capability of the lightmeter, especially in low light situations.
Later models Spotmatic F, Electro Spotmatic, ES, and ESII were capable of open-aperture metering when used with Super Multi Coated (S-M-C) Takumar lenses with an aperture coupling prong in the lens mount.

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 US and had an electronic interface for specific Honeywell Strobonar electronic flash units.