Carl Zeiss Sonnar 40mm f/2.8 (Classic)

The choice on a Rollei 35 was always Tessar or Sonnar, and once you have shot both you stop pretending it is close. The four-element Tessar f/3.5 is a fine little lens that gets crisp by f/5.6. The Sonnar 40mm f/2.8 is the one people actually chased. More glass, two-thirds of a stop of extra speed, and a contrast curve that snaps midtones into place earlier than the Tessar ever manages. On the Classic, the 1990s reissue, you get the same Zeiss optical recipe that made the original Rollei 35 S the camera people kept in a coat pocket for thirty years.

Wide open at f/2.8 it is already usable, sharp in the center with edges that tidy up by f/4 and go genuinely bitey from f/5.6 to f/8. This is not a bokeh lens. Forty millimeters at f/2.8 on full frame gives you mild subject separation at close range and not much else, so out-of-focus areas read as smooth and slightly nervous rather than creamy. What you buy a Sonnar for is the rendering up front. The blacks go deep and color saturates without turning harsh. Flare control is the surprise: shoot into a window or a low sun and the frame holds together instead of washing out. Coatings on the Classic era are good enough that you can be careless with backlight.

The catch is the camera, not the glass. There is no rangefinder. You scale focus, which means reading the distance scale and guessing, or stopping down and trusting depth of field to bail you out. Set the lens near the hyperfocal mark, around seven meters at f/8, and everything from roughly three and a half meters out to infinity falls into focus. That is exactly how most people shoot it on the street. Wide open at minimum distance is where you blow it, so f/2.8 portraits demand discipline.

It runs a between-the-lens leaf shutter, which is the practical reason this camera still earns a place in a bag. Flash syncs at every speed up to the top of the dial, so you can drag a strobe in bright daylight to fill shadows without the focal-plane sync ceiling that limits an SLR. If you are balancing fill flash against ambient, meter the background first in Zone Light Meter, then set the flash for the foreground, since the leaf shutter lets you pick any speed you want. Check the unusual 30.5mm filter thread before you go shopping for an ND or a yellow filter. Those rings are small and not always cheap.

Today the Rollei 35 Classic trades on reputation and pocketability, cross-shopped against the Olympus XA and the Minox 35. The XA is faster to focus thanks to its rangefinder. The Rollei answers with a sturdier all-metal body and the Zeiss name on the front. People buy it knowing the zone-focus tax. They keep it because few cameras this small put a lens this good in a coat pocket.