Leica Summicron-M 90mm f/2 (v2)

Walter Mandler designed this one in Canada, at Leitz Midland in Ontario, and it ran from 1980 until the APO version replaced it in 1998. Mandler's whole reputation was squeezing high speed out of designs that stayed correctable, and the brief here was a fast short telephoto for the M rangefinder that a working photographer could actually carry. The earlier 90mm Summicron was a six-element design and a heavy thing to hang off a small body. This second version came down to five elements in four groups and shed real weight, which matters when the lens is riding on a little M all day.

Wide open at f/2 it is sharp in the center and a little soft at the edges, with a gentle glow on high-contrast edges that smooths skin without going mushy. Stop to f/4 and the corners snap into line; by f/5.6 the whole frame is clean and contrast climbs. Then there is the out-of-focus rendering, which is the part people stay for. Backgrounds go to a smooth wash, no nervous edges, no onion rings, just falloff. At 90mm on a rangefinder you also get genuine subject separation, which is the practical argument for this focal length over the 75.

It is a portrait lens first. Head-and-shoulders work, environmental portraits, the occasional bit of candid street where you want compression and reach. The catch with any fast 90 on an M is focus. The rangefinder base length is fine, but at f/2 your depth of field is paper-thin at portrait distance, and a slightly miscalibrated body or a rushed focus pull will land the sharp plane on an ear instead of an eye. That is the honest weakness, and it is a rangefinder problem more than a lens problem, but it is real and you feel it.

Today it sits in the affordable-Leica tier, which is an odd thing to be able to say at all. People cross-shop it against the later APO-Summicron 90mm ASPH, and the APO wins on outright sharpness and contrast wide open. But the v2 costs a fraction of the APO, and a lot of shooters prefer its slightly softer, more forgiving wide-open look for faces. The 55mm filter thread is shared with several other M lenses of the era, so a single set of filters covers most of the bag.

One metering note. Because it opens to f/2 you can hand-meter and shoot in light where a slower 90 would force a tripod, so set the working aperture in Zone Light Meter and let it hold your shutter floor while you read the scene. There is no leaf shutter and no extension to worry about; this is a straight optic on a focal-plane body, so what the meter gives you is what you set. Mind the thin depth of field at f/2 and meter for the plane you actually intend to be sharp.