The Asahi Pentax S1a is a 35mm film SLR from the M42 screw-mount era of Asahi Optical's Pentax line. It was positioned within the company's earlier Spotmatic-period range and is sought today by collectors of vintage Japanese SLRs rather than as a working tool.

Sales data for the Pentax S1a is very thin: the only verified UK auction record on file is a single hammer result of £25 in June 2023, so the documented saleroom value sits at the low end of vintage SLR pricing. With one data point it is not possible to give a reliable range or median, and what an S1a is worth today in 2026 will depend heavily on cosmetic condition, working shutter speeds and whether a period lens is included.