The T mount is a 42mm screw thread with a 0.75mm pitch, also called T2. It is not interchangeable with M42, which shares the 42mm diameter but uses a 1mm pitch. A T-mount lens takes a camera-specific T-ring adapter, so the same lens can be used on nearly any SLR or mirrorless body.

1 lenses (1 good)

IR Focal
Length
Minimum
Aperture
Lens Filter Weight Notes Images
Good 35mm ƒ/3.5 Kyoei / Kuribayashi Clone 35mm F/3.5-22
⌀34mm(?) 149 g No hotspots or ghosting at any apertures. The left and right 3rd of the frame is very soft and smeared, though this isn’t specific to IR and could be my copy, this is a very old lens. Michael Piantedosi  

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T Mount Lens Mount Adapters

Use an adapter to mount these lenses to many mirrorless cameras.

B&H - T Mount lens mount adapters

Adorama - T Mount lens mount adapters