Pentax Super-Takumar 50mm f/1.4

Asahi built this lens to anchor the Spotmatic system, the M42 screw-mount body that put through-the-lens metering in front of a generation of amateurs in the mid-1960s. Pentax needed a fast standard prime to sit at the front of that kit, something that could shoot a stage or a dim room wide open and still resolve. The Super-Takumar 50mm f/1.4 was the answer, and it arrived in two flavors people still argue about: the early 8-element version that ran roughly 1964 to 1965, and the 7-element redesign that took over from 1965 and made up most of the production through 1971. Both are double-Gauss-derived designs, with the 8-element adding an extra element over the standard form, and both single-coated, both with the heavy machined feel of a lens meant to be serviced rather than thrown away.

Wide open at f/1.4 it glows. There is a slight veiling on highlights and the corners give up entirely, but the center holds a usable image and portrait shooters chase exactly this softness on purpose. Stop down to f/2.8 and the center snaps into real sharpness; by f/5.6 the whole frame is crisp and contrast climbs. The bokeh is smooth and rounded, no nervous edges, no swirl, just clean separation that falls off gently behind the subject.

Here is the part people get backwards. The radioactive, tea-colored copies are the later 7-element ones, not the early 8-element. Asahi used thorium glass in that 1965 to 1971 redesign, and over decades it yellows into an amber cast and reads mildly radioactive on a Geiger counter, harmless at arm's length but real. The early 8-element version uses no thorium and is far less prone to amber discoloration, which is the copy collectors prize and call the Zeiss killer. If your sample has gone visibly amber, you own a 7-element. You can bleach it back under UV light over a week or two, or shoot through the warmth and let it flatter skin on color negative. On black and white it costs you nothing.

Flare is the honest weakness. Point it near a window or a streetlight and the single-coated elements throw veiling haze and a real drop in contrast. A hood helps a lot. Multicoating did not arrive until the Super-Multi-Coated Takumar that replaced this lens, so if you need clean backlight, reach for that one or a newer prime.

People cross-shop it against the Canon FD 50mm f/1.4 and the Nikkor 50mm f/1.4, and the Takumar usually wins on build and focus action, which turns long and smooth across the throw. It is cheap, it adapts to nearly every mirrorless body through a simple M42 ring, and that keeps it in working bags fifty years on. The metering note is straightforward: this is a fast prime, so meter it wide open in low light. Drop the iris to f/1.4, take the reading with Zone Light Meter, and you get a true measure of the dim scene instead of a guess made two stops down. The 49mm front thread takes common filters if you want an ND for wide-open work in daylight.