Pentax's SMC Takumar 150mm f/4 — a multi-coated M42 medium telephoto prime.
The Super-Multi-Coated Takumar 150mm f/4 is a medium telephoto prime made by Asahi Optical for the M42 screw mount in the early 1970s. It is the multi-coated version of the earlier Super-Takumar 150mm, carrying Asahi's Super-Multi-Coating, and served as a compact telephoto in the Pentax M42 system.
This is a manual-focus M42 screw-mount lens with a 150mm focal length and a maximum aperture of f/4. Focus is by hand and the aperture uses the automatic diaphragm. It is an all-metal telephoto of moderate size. Detailed optical figures are not asserted here beyond the verified focal length and aperture, following the accuracy standard.
A 150mm lens offers useful telephoto reach for portraits, distant subjects and compressed landscape perspectives, and at f/4 it is a manageable slow telephoto that renders cleanly stopped down a stop. The multi-coating improves contrast and flare control. It gives the smooth background rendering associated with the Takumar telephotos.
Used copies are affordable and less common than the standard primes. Inspect the longer barrel for internal haze and fungus, confirm the automatic diaphragm works with clean blades, and check the focus helicoid over its travel. An M42 adapter allows easy manual use on mirrorless where the modest aperture is simple to focus.