Yashica's Yashinon DS-M 55mm f/1.2 — a very fast multi-coated Japanese M42 standard prime.
The Yashinon DS-M 55mm f/1.2 is a Japanese very fast standard prime made in M42 mount by Yashica under the Yashinon name. The DS-M designation marks the multi-coated screw-mount version, and this was the flagship fast normal lens of the Yashica M42 range, a sought-after fast fifty.
This is a manual-focus M42 screw-mount lens with a 55mm focal length and a very bright f/1.2 maximum aperture, with multi-coated optics and an automatic diaphragm. Focus and aperture are set by hand on the barrel. It is a large, heavy all-metal fast standard prime. Detailed element figures are not asserted here beyond the verified focal length and aperture.
The slightly-long 55mm with a very fast f/1.2 aperture suits portraits and low-light work, giving very shallow depth of field for strong subject isolation and a distinctive glow wide open. It is soft and dreamy at maximum aperture, firming up stopped down, and is chosen for the characterful rendering of a fast normal lens.
Used copies are sought after and priced above the ordinary standards owing to the fast aperture. Inspect the large elements for haze, fungus and cleaning marks, confirm the aperture blades are clean and oil-free, and check the aperture-ring and focus feel. Verify the M42 mount. An M42 adapter makes it a prized fast standard on mirrorless.