KMZ Helios-44M 58mm f/2

A small pin at the back of the mount is the reason the Helios-44M exists. KMZ brought it out in 1972 for the generation of Zenits, the EM and later the TTL, that carried a plunger to press that pin at the moment of exposure. The M marks the automatic, jumping diaphragm: the iris sits wide open while you focus and compose in a bright finder, snaps down to the taking aperture as the mirror goes up, and springs back open afterwards. On the preset 44-2 you closed it by hand for every frame. This one shipped as the kit lens on the Zenits that could drive it, which is why so many still turn up attached to a body.

Inside, KMZ left the optics alone. It is the same six-element double Gauss descended from the Zeiss Biotar, with a usable centre at f/2, soft corners and low contrast. Busy backgrounds like foliage can swirl around the subject, and that rendering is what turned it into a portrait and video favourite long after production ended. Stopped down to f/5.6 or f/8 it sharpens up across the frame. Point a single-coated copy anywhere near the sun and you get veiling haze plus a trail of coloured ghosts, an effect plenty of buyers go looking for on purpose.

Count the blades before you buy. Early 44M lenses have eight, along with an A/M switch, so you can stop down by hand for depth-of-field preview or on a body with no pin. From the 44M-4 onward the iris drops to six. At f/2 you won't see a difference. At f/2.8 to f/4, where a lot of portraits get made, out-of-focus highlights turn hexagonal on the later lenses and stay closer to round on the eight-blade ones. The filter thread grew too, to M52 x 0.75, so the 49mm filters from a 44-2 will not fit.

Late in the 1980s production of the threaded MC Helios-44M-4 moved from Krasnogorsk to the Valdai plant. At Valdai the multicoated lenses were bench-tested for resolution and the grade went into the name: an MC 44M-5 measured 40/20 lines/mm, a 44M-6 reached 45/25, a 44M-7 managed 50/30. Nobody touched the optical formula. A -7 is a copy that passed a stricter test, and the multicoating on all of them cuts back much of the flare that defines the older single-coated lenses.

Only pressure on the pin closes the iris, and that dependence is the real limitation: on a body without a plunger, or on an adapter that leaves the pin alone, a copy with no A/M switch shoots at f/2 whatever the ring says. Mirrorless shooters get around it with an adapter that has a ledge to hold the pin in. Decades-old springs and hardened grease also leave some irises sticky or slow, so push the pin a few times and watch the blades snap shut before you pay.

A 44M usually sells for less than a Super-Takumar 55mm f/1.8, and wide open the Takumar is generally reckoned the crisper lens. The Helios gets bought for how it draws. Chasing that wide-open look outdoors runs into a practical wall: f/2 on ISO 400 film in sun needs a far faster shutter than the 1/500 top speed of a Zenit-EM or TTL, so a 52mm ND has to soak up the difference. Enter its filter factor in Zone Light Meter and the reading carries the lost stops.