Carl Zeiss Planar T* 135mm f/2 (C/Y)

Put the Nikkor 135mm f/2 next to this one and the Nikon is sharper in the dead center wide open. Then you shoot both at portrait distance and stop worrying about line pairs. The Planar's whole argument is the transition: how a face sits inside that out-of-focus field, how skin holds micro-contrast without going harsh, how the background dissolves instead of breaking into nervous edges. That is what people buy a fast Contax/Yashica tele for, and at 135mm f/2 it is about as concentrated as Zeiss got it on 35mm.

It is a 5-element, 5-group design, an asymmetric telephoto formula (a hybrid of the Ernostar and double-Gauss types), not the classic symmetrical double-Gauss the Planar name implies for shorter focal lengths. Worth knowing, because most fast 135s of the period went the Sonnar route (Zeiss built one of those too, the Sonnar 135mm f/2.8). Five air-spaced elements is a lean count for a fast tele, and the trade is size: this lens is a brick. The T* multicoating earns its keep, though. Shoot into a window backlight and it holds contrast where a single-coated rival of the 1970s would haze over.

Wide open it is usable but soft, with the rendering doing the heavy lifting rather than outright resolution. By f/4 to f/5.6 it tightens up nicely across most of the frame. Bokeh stays smooth and slightly soft-edged, never the busy double-line you get from over-corrected glass, and the 8-blade diaphragm keeps specular highlights as clean rounded discs near center. Color runs warm and a touch more saturated than the Japanese 135s of the era, with contrast a notch higher. None of that is mystique. It is what shows up on the film.

The honest weakness is focus. You are hand-focusing f/2 at 135mm, which means depth of field measured in millimeters at close range, and on an SLR screen that is unforgiving. Miss by a hair and the eyelashes are sharp while the iris is not. The other cost is the price you pay used. Clean C/Y copies trade well above the equivalent Canon FD or Nikkor because Contax glass picked up a following and the supply is finite.

Who reaches for it: studio and editorial portrait shooters who want compression and separation without going to a 180, plus people adapting it to mirrorless bodies where focus peaking finally tames that razor plane. It gets cross-shopped against the Canon FD 135mm f/2 (cheaper, faster to find) and, for the deep-pocket crowd, the Leica 135 telephotos. People keep paying for the Planar because of how it draws a face, not how it scores on a chart. Practical note: at f/2 in dim light you are metering wide open with very little margin, so when you stop down to shoot, meter at working aperture in Zone Light Meter and place your skin tone deliberately rather than trusting an averaged reading. This lens rewards exact exposure as much as exact focus.