These structurally similar T4/TX mount 200mm vivitars are the successors to the rather different but also tokina made
T4 200mm f3.5 with tripod mount. The T4 (pic 4) has a milled focus ring. The TX's (pics 1-3) have a rubber grip and are normally reckoned to be the equivalent tokina RMC lens but with the swappable TX mount.
This lens was itself succeeded by the fixed mount
komine made 200mm f3.5.
TX mounts were made in PK, M42 and other camera mounts of the era (but not PKA).
PDFof a TX mount user manual here. And
this page on mflenses.com shows the difference between T4 (=1st version) and TX (=2nd version) mounts.
Optics: 5 elements in 5 groups (based on optical description for tokina 200mm)'
Filter: 58mm
Aperture: f3.5 - f22, one stop clicks.
Iris: 6 blades,
Built in short hood.
Focus: ~ 300° throw, anti pentax.
Weight: ~512g w/o mount.
Length: ~ 108mm at infinity focus.
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