M42 mount variations

[GrahamS]

I have a Jupiter 8, f2 50mm lens in what appears to be M42 mount, but the thread is finer than the standard M42. Manufacture date is 1977. Can anyone tell me what camera this mount is for?

[alexvaras]

Has M42 a pin for the aperture? Has this pin this lens?

[titrisol]

Are you sure that isn't M39 (Leica thread)?

The only other option would be M42x0.75 ? That would be T-mount
I think Cambridge camera was the one importing these

[GrahamS]

Has M42 a pin for the aperture? Has this pin this lens?

No, aperture is preset.

[GrahamS]

Are you sure that isn't M39 (Leica thread)?

The only other option would be M42x0.75 ? That would be T-mount
I think Cambridge camera was the one importing these

Thanks, you are correct. It measures 42 x 0.75mm That is "T" mount.

[alexvaras]

I guess every kind of mount has a J-8

[GrahamS]

Now here's a thing. I screwed the J-8 into a T-Mount adaptor (for Nikon F) and it won't focus anywhere near infinity. Farthest focus distance is around 30cm. It does, however, screw into the T-Mount perfectly. Would there have been a T-Mount for a rangefinder camera?

[Brazile]

Would there have been a T-Mount for a rangefinder camera?

That would be a bit surprising, but possible, I suppose. Apparently it was intended for a shorter flange register distance than Nikon, anyway. Nikon F is 46.5mm, perhaps Canon R/FL/FD mount at 42mm? More modern Canon is 44, of course.

Robert

[GrahamS]

Problem solved! I stupidly did not realise that the knurled ring at the back of the lens was actually an adaptor screwed onto the lens. It was very tight but it did come off. On the rim, it says "M39 Leica - T2"The lens itself is actually M39 Leica mount, as it should be. Like I said, age usually brings wisdom, but sometimes it shows up alone - you never know.

[alexvaras]

Then it's for first Zenit cameras if Im not wrong.