The Asahi Pentax 15mm f/3.5 SMC is an ultra-wide-angle prime designed for the Pentax K bayonet (with earlier M42 screw-mount counterparts), aimed at 35mm film SLR users who needed an extreme angle of view without resorting to a fisheye projection. It belongs to Pentax's SMC era of multi-coated optics, intended for landscape, architectural and reportage work where rectilinear correction across a very wide field was the priority.

UK auction activity on this lens is thin — the only verified saleroom result on file is a single hammer price of £460 in November 2025, so today's market read is necessarily based on that one data point rather than a broad spread. As a wholesale figure (auction hammer results exclude buyer's and seller's commission), it suggests clean copies sell for somewhere in the mid-hundreds at saleroom level in 2026, though more sales would be needed before a confident range or median could be quoted, and clean, unmolested examples typically command a premium over user-grade glass.