KOMZ Jupiter-37A 135mm f/3.5

Twelve blades on a slow 135. Put a sitter at 1.2 metres, set f/5.6, and let a hedge of backlit leaves sit ten metres behind them: the specular highlights in those leaves stay close to round, because a twelve-sided opening has almost no corners to show when you stop down a little. That 1.2 m close focus fills a 35mm frame with a face, so the Jupiter-37A earns its keep at head-and-shoulders distance far more often than across a field.

KOMZ in Kazan made it, starting from the Zeiss Sonnar 135mm f/3.5 and recalculating the design for newer glass types. It stayed a simple four elements in three groups, and the barrel is short and light for a 135. The "A" refers to the rear mount, an interchangeable adapter; most copies you find wear the M42 one. A 1985 price list puts it at 100 rubles. Around 1980 a multicoated MC Jupiter-37A appeared, and some copies from that year carry the Moscow Olympics logo on the barrel and on the case.

Owners usually describe the drawing as classic Sonnar. Wide open, people report enough bite at the eyes for portraits, with out-of-focus areas that fall away softly; by f/5.6 to f/8 most say the whole frame firms up. Four elements in three groups means only six air-to-glass surfaces, and on the single-coated copies that low count does a lot of the work of holding contrast. A low sun just outside the frame can still lay haze over the shadows on those, so screw a deep hood into the 52mm thread. If you shoot into the light often, hunt for the MC version.

Then there is the diaphragm, and it is the real weakness. It is a clickless preset design with no automatic stop-down, so the camera never closes the aperture for you. You set the preset ring to your taking aperture, focus wide open, then twist the second ring down to that stop before you fire. Rush the shot and forget to turn the ring, and you get a frame shot wide open. On a Zenit with stop-down metering the finder goes dim at f/8, and in shade at dusk reading the needle gets close to hopeless. Video shooters adapt the lens for the same ring that annoys stills shooters: aperture changes are smooth and silent.

Because the finder darkens the moment you turn that ring, it makes sense to meter off the camera. Take a handheld reading in Zone Light Meter, set the shutter speed it gives for your preset aperture, and keep the lens wide open for focusing right up until you stop down and press the release.

Most buyers cross-shop it against its own family. The Jupiter-11A is a little slower at f/4 and also lacks an automatic diaphragm. The Tair-11A gets you f/2.8, but it is a bigger, heavier lump to carry. Outside the Soviet catalogue, the Pentax SMC Takumar 135mm f/2.5 adds an automatic diaphragm and roughly an extra stop. For slow portrait sessions on a Zenit, where you have time to turn a ring and the blade count shows in every background, the 37A is the one I would pack.