Pentax's TTL screw-mount SLR — the Spotmatic SP, stop-down metering, M42 mount, 1964.
The Pentax Spotmatic SP, launched in 1964, brought through-the-lens metering to Asahi's screw-mount line and became one of the most widely sold SLRs of its era. It sat as the flagship of the Spotmatic family and helped popularise built-in TTL metering across the industry. It marked the transition from the earlier unmetered S-series to a metered but still fully mechanical design.
This is a 35mm film SLR using the M42 screw lens mount, taking the wide range of universal M42 lenses. It has a horizontal cloth focal-plane shutter running from 1 second to 1/1000 plus B, and a fixed eye-level pentaprism with an instant-return mirror. Metering is stop-down TTL: a switch on the body closes the lens to the working aperture and a match-needle display guides manual exposure. There is no automatic mode; the shutter is fully mechanical and fires without a battery, the cell powering only the meter.
The Spotmatic SP suits students, travellers, street and documentary photographers, and anyone wanting a robust metered screw-mount body. It handles smoothly, with a bright finder and simple stop-down metering, though that stop-down step is slower than the open-aperture metering that came later. It is a dependable, long-lasting camera well matched to the huge stock of M42 lenses.
As a mid-1960s body, several checks matter. Inspect and expect to replace perished foam light seals and mirror-damper foam. Test the cloth shutter for pinholes, capping and even speeds. The meter was designed around a 1.35V mercury PX625 cell, now banned, so readings from a modern 1.5V alkaline replacement can be off unless an adapter or recalibration is used. Check the pentaprism for desilvering or foam haze, and test the advance and rewind. Fully mechanical operation means it still shoots with a dead battery.