[Yuval]

I have an old Soligor 300mm f/5/5 with a strange-looking mount, which appears to have a female coupling with a metal cap attached, clearly marked 'PX' in green.

I have no idea to which camera model this should fit, so that I can look for a proper mount-adapter, to test the optical quality of this particular lens.

Any one with knowledge of 70's gear, please help :

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Last edited by Yuval; 02-23-2014 at 11:11 PM. Reason: spelling

[Not a Number]

The lens is using an interchangeable T4 mount. The mount adapter marked "PX" from the look of the rear cap is an M42 screwmount. Same idea as the Tamron Adaptall system. Take off the rear cap and see what mount is under there.

T4 proceeded the TX system and was followed by the Adaptall. T4 mount adapters can by used on TX lenses but not the other way around.

If it is a M42 mount you can use a m42 adapter. Or you might be able to find a T4 K mount adapter (if they made one).

http://www.cameramanuals.org/booklets/vivitar_t-4_system.pdf

[Yuval]

Thanks for the info - I was not aware of this TX standard - much appreciated.

However, the cap-looking thingie on the adapter will not budge no-matter-what, and on close inspection (with a lupe), it looks like the whole shabang (the "cap" and the "adapter") is one fused unit.

So, I'll take your word for it, and try my best to unscrew the mother off.

One more question if I may :

If I am to attach an M42 to "my camera" adapter, between the beast and my camera - won't it "throw off" the hyperfocal point of the lens (in regard to the optically planned lens to sensor distance) ?

[Not a Number]

It depends on the camera you are attaching it to and the M42 adapter you use. If you are attaching it to a 4/3 camera, Canon EOS or Pentax K mount you can get adapters without optics to give you focus at infinity. Other camera mounts probably require optics to achieve infinity focus. Without optics the adapter usually work as a short extension tube and you can use the lens for close-up or macro work.

The T4/TX adapters would have the correct register length so the lens would work properly with the intended camera.

The rear cap might be screwed on instead of a friction mount. One of those rubber web grip sheet might help you to get a grip on the cap.

See this thread if using EOS mount
https://www.pentaxforums.com/forums/76-non-pentax-cameras-canon-nikon-etc/225...s-adapter.html

The recommended adapter for K mount is the OEM Pentax one. There are knock-offs but it is recommended you remove the retaining spring clip.
Pentax Mount Adapter K reviews - Pentax Camera Accessory Review Database