New/old lens won't reach infinity.

[gone]

I bought a nice Soligor 105 2.8 lens in m42 mount and it won't hit infinity. It has to be held a couple of inches away from my Pentax camera. There's a scratch on the front bezel where the tool slipped, so it's obviously been apart.

Looking at the same lens online, it appears the helicoid threads have been started at the wrong place. The other lenses rear lens group extends out of the lens at infinity, while mine is recessed.

Is it a PITA redoing this myself? It's an old lens, maybe 50-70 yars old or more. I've taken apart and cleaned lenses before, but I always marked things so they went back together right. Getting the threads re-started in the right place is probably going to be another matter. Lots of trial and error?

 

[AgX]

Lots of trial and error?

Well, you know in which direction you should search for the right starting threads.
This would make it instead a kind of educated guess...

 

[Sirius Glass]

From the description the lens is out of alignment in multiple ways. If cost effective the lens needs to be put on an optical table and aligned and adjusted back to the proper configuration.

 

[xkaes]

Consider that whoever messed with it screwed it up. You don't even know if all the pieces are there. I hope you didn't pay much for it. How much time do you have to waste?

 

[gone]

The only thing out of alignment is me. I'm an idiot.

Turns out the lens is a T-mount, and probably needs all that extra space on an adapter to reach infinity. And, they made these lenses in a bewildering amount of mounts, the ones I looked at w/ the rear element in a different place were not exactly the same lens.

Thinking it was M42, I also attempted to thread this lens into an M42 to K adapter w/ no success. It didn't work.

Got lucky just now and bought a pre set lens like this one in Nikon F mount for $50. Of course, the only Nikon camera I own is listed for sale......... I fully expect the camera to sell the day the lens arrives. That's how things have been going.

 

[shutterfinger]

Back in the day T mount was used so the lens could be adapted to different camera makes rather than making versions for each camera make.
google search t mount to m42 adapter -

https://www.bhphotovideo.com/c/product/1457964-REG/kipon_t2_m42_opteka_t2_to_m42.html

https://www.bhphotovideo.com/c/product/1401066-REG/nisha_tmts_t_mount_adapter.html

 

[btaylor]

Why not buy the Soligor T adapter for the Pentax K mount you are trying to get to? Wouldn’t that solve the issue?

 

[AgX]

The only thing out of alignment is me. I'm an idiot.

Turns out the lens is a T-mount,...

Thinking it was M42, I also attempted to thread this lens into an M42 to K adapter w/ no success. It didn't work.

Well, not many fellows here dare to admit such...

And be assured you are not the only one to mix up T with M42. Welcome to the club.

 

[xkaes]

Yes, a T-mount and an M42 mount are both 42mm wide. The only difference is the pitch. One is 1mm, the other 0.75mm.

 

[xkaes]

Why not buy the Soligor T adapter for the Pentax K mount you are trying to get to? Wouldn’t that solve the issue?

I does not have to be a Soligor T-adapter. It can be any T-adapter. A T2 would be better since it is adjustable.