Leica APO-Summicron-M 90mm f/2 ASPH

A subject's eyelashes wide open at f/2, two feet away, with the background already gone to butter behind them. That is the frame this lens owns and almost every other 90 on the market loses. Most fast short teles need a stop or two before the plane of focus snaps clean. This one is there at f/2, center to corner, the moment you open it. Reviewers put its wide-open resolution next to the Zeiss 100mm Makro-Planar, which is a microscope wearing a lens hood, and the Leica holds the comparison.

The optical formula is unusually lean for what it does: five elements in five groups, one of them aspherical. When Leica shipped it in 1998 that asphere was their first polished one rather than pressed, which is the boring-sounding detail that actually mattered, because polishing let them use the anomalous-dispersion glass the apochromatic correction needed. APO here is not a sticker. Chromatic aberration is corrected to the point where you have to manufacture an extreme backlit edge to find purple fringing at all, and even then it is faint. Color comes through neutral, contrast is high without going harsh, and there is no swirl, no character, no vintage anything. That is either the whole point or the whole problem, depending on who you ask.

Bokeh is the surprise. A lens this corrected has every excuse to render backgrounds nervously, and it does not. Out-of-focus areas go smooth and round, and the falloff from sharp to soft is gradual rather than the abrupt cardboard-cutout look you get from some clinical designs. Studio and editorial portrait shooters use it for exactly this: a face that resolves down to skin texture sitting in front of a background that stays calm. It also doubles as a discreet rangefinder long lens for documentary and candid work, where 90mm gives you a little reach without the size of an SLR tele.

The honest weakness is the rangefinder itself, not the glass. At f/2 on a 90mm the depth of field is paper-thin, and the M's mechanical rangefinder patch is right at the edge of what can reliably nail focus at that distance. Miss by a hair and the eyelashes you came for are soft while the ear is perfect. On a digital M you chimp and reshoot. On film you find out at the lab. This is a lens that rewards a calibrated body and a steady hand, and punishes a tired one.

It is not cheap and never has been, but it sits below the f/1.5 Summilux and Noctilux glamour pieces while out-resolving most of them, which is why people who care more about the negative than the badge keep buying it. The cross-shop is the older pre-ASPH 90 Summicron (softer, cheaper, more "Leica look") or the 75mm APO if you want the same correction at a tighter working distance. One field note: at f/2 you are metering for the deep shadows that this much sharpness will render in full detail, so set Zone Light Meter to place your shadow values where you actually want them and let the highlights fall. The 55mm filter thread takes a standard polarizer or ND if you are shooting wide open in daylight and need to kill a stop or two.