Industar's later lanthanum Tessar — Industar-61 L/D 55mm f/2.8 in M39, crisp, characterful, great value.
The Industar-61 L/D is a later Soviet standard lens of Tessar type, made for the M39 (Leica thread) rangefinder mount and used on FED and Zorki bodies. The 'L/D' designation refers to the lanthanum glass used in its construction, a marker of the improved optical glass in this generation of the Tessar-derived Industar line.
This is a manual-focus, rangefinder-coupled Leica Thread Mount lens with a 55mm focal length and an f/2.8 maximum aperture. It uses the 39mm rangefinder thread and mounts on Leica screw bodies, subject to the slight Soviet-versus-Leica register difference. As a Tessar-type design it is compact, and it is among the later and more refined standard lenses in the Soviet M39 range.
The Industar-61 L/D is known for crisp, contrasty Tessar rendering and, on many samples, a distinctive out-of-focus highlight shape produced by its aperture blades, which some photographers actively seek. It works well for general, travel and street use, and the slightly long 55mm framing suits casual portraits. Rendering varies between samples but the sharpness is a consistent draw.
On the used market the Industar-61 L/D is a well-regarded value pick among Soviet standards, combining low price with the later lanthanum glass. Soviet QC varied by year and factory, so check each sample individually. Adapting to Leica may need a register check or shim. Inspect for haze and coating condition, feel the aperture ring for smooth clicks, and test the focus. It adapts readily to mirrorless with an M39 adapter.