Carl Zeiss Sonnar 85 cm f2

This lens has been with me for a while. It's been a faithful portrait lens, but not much else. Why? Because it was adapted by a previous owner. The lens used to be in the Contax rangefinder lens mount (outer bayonet), but when I bought it, it was already adapted to M42. The M42 mount was riveted to the lens, so I could not remove it and restore it to the original Contax rangefinder mount. This means it lost infinity focus and the focus scale shifted. Luckily, headshots and tighter portraits were still possible up to 4–5 metres away.

Adapting lenses can be tricky between different systems. Some adapters need a glass element to retain infinity focus. Others are just simple spacers with different mounts on each side. An easy way to tell if a lens can (theoretically) be adapted to a different system is to check a chart of lens flange focal distances. If the receiving camera's flange distance is less than the lens's, it should be possible. In the case of this lens, the M42 flange distance is far greater than the Contax one. In short: an M42-mount camera needs 45.46mm from the lens flange to the film plane to focus properly. A Contax rangefinder lens needs 34.85mm. Since you can't shave off the camera body, most people trying to adapt a lens like this put on a new lens mount, which acts like an extension tube.

A stepless aperture with 16 blades, solid construction, and smooth focus. This lens has good ergonomics, especially if you're used to older lenses. The aperture ring is near the front and is steepless.

I pretty much got what I expected optically from a lens this old (1939–1942). Even though it's coated, lens flare is a big problem. A lens hood, when shooting outdoors, will improve your photos by a ton. Sharpness isn't great, although when you stop down, everything but the far corners is usable. Contrast is a bit lacking, which isn't a big deal for portraits. I love the subtle colors you get from Sonnars!

The Sonnar is a lovely lens design. The 5cm 1.5 is one of my all-time favourites, and the 85cm f2 does not disappoint when you work with its limitations. I had a few more than a normal copy would have, but still, it's been pleasant. If you're considering a vintage 85cm but are on a really tight budget, you can alternatively go for a Jupiter-9, which is a Soviet-built copy of the Sonnar.