Need help identifying a Vivitar lens mount

I recently purchased an old manual Vivitar Lense (10$!) to play with and cannot identify the mount. I just hacked a plastic body cap and put it on my Canon 450D (EF mount) and cannot get infinity focus nor can I focus farther then about 30 feet. This tells me that my cheapo adapter (about 5mm thick) puts the lens too far out. Identifying the actual mount of the lens would allow me to know the precise flange focal distance and go on from there.

I found this site detailing the lens: but being real new to photography cannot find references to T Mount lenses anywhere. It has a small lever on the mount that can control the aperture (presumable from the camera body)

Here are some pictures of the beast with transcripts of the text on it:

  • Vivitar 85-205mm 1:3.8
  • Macro Focusing Auto Zoom
  • No. 22539274 diam:
  • 58mm Apertures from 3.8 to 22
  • Lens made in Japan Patents Pending N/F

Thw Whole Beast
Mount overview
Aperture Control
Mount Aperture Lever