Industar-50 50mm 𝒇3.5 Lens Review

A Soviet M39 Pancake Lens for Miranda, Zenit, Pentax, and Praktica SLRs

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Industar-50 50mm 𝒇3.5 “Eagle’s Eye” lens is a compact Soviet-made lens with great creative potential and modest flaws. It uses an unusual (for SLRs) M39 screw mount (similar to Leica Thread Mount) with a 45.2mm  flange distance — which works perfectly with SLRs, particularly Miranda Sensomat, on which it was tested with an adapter.

The M39 SLR lens mount.

I got this lens for its compact size to mount on my Miranda Sensomat film SLR with an M44 to M39 lens adapter. The M39 lens mount is typically used for host Soviet rangefinder lenses, like FED-2 — a Leica lookalike. But as you may know, rangefinder and SLR lenses are not interchangeable due to the significantly differing flange focal distances.

That is, trying to mount a rangefinder lens on an SLR would cause: 1) the distance markers on the lens not to match the actual distance that’s in focus and 2) the inability to focus on infinity. The farthest focus distance in such case may be about 20cm/8” to the film plane (measured with Industar-61 L/D) — which makes the lens useless for most applications other than macro photography.

Industar-50 on Miranda Sensomat film SLR with an M44 to M39 lens adapter (with a waist-level viewfinder attachment).

Lens mounts and adapters are overwhelmingly-diverse and often confusing — especially when examined throughout centuries’ worth of interchangeable-lens designs. Industar-50 is one of the outliers from the expected norms (M39 being used predominantly on Leica rangefinders and Leica clones with slight differences between the genuine German mounts and their adjacent counterparts).

Designed for SLRs with a 45.2mm  flange distance that rests comfortably on deeper SLR bodies, Industar-50 works perfectly (with an adapter) on my Miranda Sensomat camera, with all the distance markings aligning correctly. Unfortunately, the camera has no control over the aperture — a common issue when adapting lenses of different systems. This makes focusing in low light a two-step process: 1) open the aperture to its widest 𝒇3.5 to let the most light for focusing, and 2) stop down the lens to an appropriate aperture for the light/shutter speed. But that’s a small price for a cheap, quality lens that renders my bulky SLR nearly pocketable.

Though I haven’t tried mounting this lens on any camera other than my excellent film SLR, it can be adapted to a large variety of film cameras, including Pentax/Praktica (M42) and digital cameras with the Sony E and Canon EF mounts.

This lens mounts natively on old Soviet Zenit SLRs, including Zenit 1, C, 3, Crystal, and 3M.

A later iteration, Industar 50-2 (black paint), uses a more-common M42 mount. I haven’t tested that version.

✪​ Note: Thank you all who helped me disambiguate some lens mount information on #BelieveInFilm Twitter and Mastodon.

Top-view of Industar-50 on Miranda Sensomat film SLR with an M44 to M39 lens adapter.

Industar-50 size, weight, build quality and ergonomics.

Industar-50 was a utility purchase: it has the right size, price, and compatibility with the camera I was using. But after testing it for a few weeks, I realized that it’s more than just a convenient attachment. This lens has a strangely beautiful way of rendering the environment while remaining reasonably sharp and distortion-free. All that in a light aluminum/optical glass package that weighs just 64g/2.3oz and measures 5cm/2” in diameter, protruding just 2cm/⅘” from the camera body when set to infinity.

The lens has a close focus of .65m/2’1½” with about 160° throw and a max aperture of 𝒇3.5 that can close down to 𝒇16. It has a 34mm filter thread

Industar-50 with Kodak Gold 200.

Industar-50 image quality.

Industar-50 is surprisingly sharp, contrasty, and free of vignetting/aberrations when stopped down. This lens resolves very well and appears to share some of its colour properties with its younger cousin — Industar-61 L/D, which tends to add a complex and faint shade of blue in some cases and produce deep, inky shadows.

While it may not be as sharp as modern lenses (even in the center), the images this lens captures are very legible and appear to have plenty of depth, despite the Industar-50’s relatively small maximum aperture.

Industar-50 with Kodak Gold 200.

Even when shot wide-open, the properties of the lens remain relatively consistent: no vignetting, sharp corners, and little swirl.

This lens can certainly flare and is thus best not to be pointed directly at the sun. But given its age, price, and the manufacturer known to build products of inconsistent quality, it’s an excellent deal.

Industar-50 painterly bokeh with Kodak Gold 200.

Where to buy your Industar-50 50mm 𝒇3.5 lens.

This lens is not rare. You can even find copies of it sold on Amazon for a reasonable price, as well as many more on eBay. They are usually marked from $15 to $70, depending on the condition.

By the way: Please consider making your Industar-50 50mm 𝒇3.5 “Eagle’s Eye” lens purchase using this link  so that this website may get a small percentage of that sale — at no extra charge for you — thanks!