Tair's 11A 135mm f/2.8 — a Soviet M42 short telephoto with round-aperture bokeh.
The Tair-11A 135mm f/2.8 is a Soviet short-telephoto prime made in M42 and other mounts, the A version being the adapter-mount variant of the Tair-11 design. Produced through the 1970s, it was a well-regarded fast 135mm in the Soviet lens range, known for its build and rendering.
This is a manual-focus M42 screw-mount lens with a 135mm focal length and a maximum aperture of f/2.8. Focus and aperture are set by hand, and the Tair-11A is noted for a many-bladed aperture that gives very round openings. It is a heavy all-metal telephoto. Exact element figures are not asserted here beyond the verified focal length and aperture.
At 135mm f/2.8 the lens is a classic portrait and short-telephoto tool, giving compressed perspective and good subject isolation. Its multi-blade aperture produces notably round out-of-focus highlights, and it renders smoothly for flattering portraits and distant detail. It is regarded as one of the nicer Soviet telephotos for its bokeh.
Used copies are affordable and popular for portraits on adapted cameras. Inspect for haze, fungus and cleaning marks, confirm the many aperture blades are clean and the preset or aperture ring works smoothly, and check the heavy focus helicoid. Verify the M42 mount. An M42 adapter makes it a favourite manual portrait lens on mirrorless.