What is attached to the mount of this lens?

[connloyalist]

I was looking through one of my eBay searches as I often do, and came across this:

https://www.ebay.co.uk/itm/Schneider-Kreuznach-Xenar-3-5-105mm-mit-Einschraubgewinde-M/133527267239

Please take a look at the pictures. I see a screw mount (presumably either M39 or M42) but there seems to be something attached to / screwed on to the screw mount. Any idea what that is? What am I looking at here?

(And yes, feel free to beat me to it if you like what you see )

Regards, C.

[DConvert]

Perhaps it's not M39 or M42, and that is simply a retaining ring. It does look very large for that I admit.

[Pancolart]

this is what you get when unscrewing all attachments / mounts. So this lens is without any mount.

[iangreenhalgh1]

92eu for that! Ridiculous, it's not worth half that. If you want a Xenar 135, get one of the common Retina DKL mount ones.

I think the one in the ebay auction is the front part of a lens for one of the more obscure mounts, perhaps Diax.

[Lightshow]

I'm not sure what is going on with it, it does look like it's missing it's mount, but it also looks like it was modded to mount to a lens board because of the leather gasket, but the rear portion has me puzzled as to if it belongs to the lens originally or if it's an add on, it almost looks like it's part of the helicoid system, the slot in the side seems like a guide rail but I can't see enough to be sure, there are definitely threads visible around the leather gasket, sadly that's the end of what I can see without having the lens in hand, it's either missing parts(a safe bet) or has extra bits, so it's definitely a bit of a gamble, do you feel lucky?

[Lightshow]

After comparing it to this lens https://www.ebay.co.uk/itm/Vintage-Schneider-Kreuznach-Xenar-105mm-3-5-Telephoto-Lens-for-M42-fit/392903054987
It looks like it's missing the body, it looks like it's been adapted to a lens board for bellows use, there is a threaded ring that matches whatever thread the optics has to attach to the body, usually it's a fine pitch thread, not as corse ad M39 or M42, the leather gasket is to help keep the lens from turning if you want to adjust the helicoid for more extension, and possibly to seal out light and possibly to not scratch the lens board.
The helicoid does look like it could be complete, so it could be adapted relatively easily with a simple tube with what ever mount you choose.

One way you would/could adapt it to a mirrorless mount is with an M39 adapter with the removable insert, figure out the thread of the optics cell, and have that thread cut into the end of a tube and the other end turned down to the O.D. of the adapter insert, RAF Camera would likely be able to do the machining, the hardest part is to figure out the length of the tube.

Or just get the lens above in my link if it's any good (I didn't look) the price is about the same.