Leica Summitar 50mm f/2 (LTM)

Shoot it wide open and the background does not just blur, it dissolves into something that looks like memory instead of a wall. That is the shot the Summitar owns. At f/2 you do not get clinical separation. You get a soft glowing core that stays usable in the center while the edges swirl, the corners fall off, and out of focus highlights smear across the frame. Modern glass corrects every bit of that away. People hunt the Summitar down precisely because it refuses to.

It arrived in 1939 to replace the Summar, a Gauss-type evolution with an extra element added for better correction. It stayed in production into 1953, when the first Summicron 50/2 took over. Prewar copies are uncoated and flare at the slightest hint of a light source, which is part of the look as much as a flaw. Postwar coated versions hold contrast better but still bloom against the sun. It is collapsible, so it pulls back into the body of a Barnack camera and vanishes into a coat pocket. That alone keeps street shooters interested.

The diaphragm is the detail that trips people up, and it usually gets told backward. Late Summitars (post-1950) use a 6-blade hexagonal iris, so stopped down even slightly the out of focus highlights turn into little stop signs. The earlier many-bladed versions keep those points round. Collectors who care about round bokeh chase the pre-1950 copies, or pay a tech to swap the hexagonal iris for a rounder one. Wide open none of this matters, since the aperture is fully open and the famous swirl lives there, strongest with busy backgrounds at portrait distance. Stop down to f/5.6 and it sharpens into a perfectly competent fifty. Contrast climbs, the swirl calms, and you would not guess the glass was eighty years old.

The honest weakness is consistency. These lenses are old, often carrying haze, cleaning marks, or separation in the cemented elements, and condition swings the rendering more than the design ever does. A hazy copy is mush wide open. A clean one is magic wide open. Buy the glass, not the listing photos. One more quirk: early units run the old Continental aperture sequence ending around f/12.5 rather than f/16, which throws anyone expecting modern markings.

Today it remains one of the more affordable ways into vintage Leica rendering. The people cross shopping it are usually weighing it against a collapsible Summicron or a Canon LTM fifty, and they pick the Summitar when they want flaws with personality instead of correctness. One metering note. At f/2 in dim light this lens earns its keep, so set Zone Light Meter to your working aperture and meter for the shadow you actually care about. Wide open, the falloff and glow mean your center exposure is the one that counts, not the edges the lens is already throwing away.