Leica Summicron-M 35mm f/2 ASPH

Wide open at f/2 the center is already sharp, and not in a polite way. This is a high-resolution, high-contrast 35 that resolves fine detail at maximum aperture and only tightens up from there. The corners clean up fast by f/2.8, and from f/4 to f/5.6 the frame is even edge to edge. If you know the lens it replaced, the pre-ASPH Version 4 from roughly 1979 to 1997, this is a different animal. That older v4 is the one Leica shooters call the King of Bokeh, a softer, lower-contrast formula famous for creamy out-of-focus rendering. The ASPH trades a good chunk of that gentleness for resolution and bite. Worth knowing before you buy, because people still confuse the two and expect the v4 look from this barrel.

So what does the ASPH actually do behind the plane of focus? It renders out-of-focus areas more nervously than its predecessor, with busier highlight discs and more outlining in some backgrounds, especially at f/2. The original version (11879) shipped with an 8-blade iris. Leica added three blades in the 2016 Version II specifically to round out the bokeh, which tells you they heard the complaints. Like most compact fast rangefinder 35s, expect some cat's-eye deformation of highlight discs toward the edges wide open from mechanical vignetting. Color runs neutral and slightly cool the way modern M glass tends to, contrast is strong but controlled, and flare resistance is solid for a lens this small. Field curvature is mild and focus falloff is gradual, which is part of why it sits a subject inside a scene so well.

This is the documentary and street focal length on a rangefinder, and the 35 ASPH is the lens most M shooters reach for to do it. Small enough to carry all day, fast enough for dusk, wide enough to place a person in their surroundings without bending faces up close. Reportage, off-the-cuff weddings, travel, long-running personal projects. It earns its keep.

The honest weakness is what you pay for the last increment of quality. A Voigtlander Nokton or Color-Skopar 35 covers most of this ground for a fraction of the money, and the f/1.4 Summilux-M 35 ASPH gets you another stop and more character in the rendering. You are paying a steep premium for Leica build, the resolution edge, and resale that barely moves. Some working photographers think that is money well spent. Others put it toward film and never look back.

Two practical notes. The 39mm filter thread is the standard Leica E39 size, so screw-in ND and polarizers are easy to find if you want to shoot wide open in bright daylight. And since there is no leaf shutter and no metering in the lens, you are metering through whatever body it is mounted on. Working at f/2 in low light, set Zone Light Meter to the actual taking aperture and let it solve the shutter speed, instead of metering stopped down and doing the offset math in your head.