[jatrax]

If you can assess to some tools that can open up the "name ring said takumar 50mm" on the front. Then you will see three screw. Loose up the three screw and you can calibrate the focus.

This is fairly simple to do if you are careful and have the right tools. I have done the process several times on different Takumars. But I am not sure there is enough adjustment to make that big a change.

[jatrax]

Then yours isn't spinning as far as it should. I'm afraid it means opening the lens for reconstructive surgery. Follow @MegaPower's suggestion. And look for out-of-place bits that may interfere with the focus.

Agree on this, I think I posted earlier that mine was 180 degrees but that was in error, I used a little mark on the ring to track and darned if there are not two such marks. So if you are not getting 240 degrees something is stopping it from rotating fully, which makes the most sense of anything so far.

I have a S-M-C 150mm that came to me with a loose screw stuck in it that prevented the focusing ring from turning fully. I opened it up and the screw dropped out, works fine now. Never did find where the screw was supposed to go. I suspect it was dropped in at the factory and never found.

[voyager13]

Thanks Rio. If there's isnt anything else I can do to fix the lens, than perhaps opening it would also be an education into the wonderful world of lenses If only I could know how to open and where to look for problems and fix them... G'night Rio.

[Arjay Bee]

If only I could know how to open and where to look for problems and fix them...

There is always this helpful thread :
Brian Ayling's photographic repair tips

Seriously though this is a common issue with lots of pointers on the web: e.g.
The Classic Camera Repair Forum: Super-Multi-Coated Takumar 50 1.4 - stuck focusing ring

[Lowell Goudge]

Perhaps someone will correct me if I am wrong, but I believe that the takumars have 3 small screws that attach the focusing ring to the focus helix internally.
These screws have washers under the head that are used to bridge the separation between the focusing collar and the helix, and usually some form of locking compoind on them. If the IP had set the lens in the window under strong light, perhaps it got hot enough to soften the locking compound and have the focusing collar slip slightly.

I am not sure on a TAK how to access the screws, but it is likely by removal of the front beauty ring.

[pacerr]

Perhaps no longer a probable cause, but my first thought was that there might have been a 'close-up/diopter' filter on the lens - perhaps mistaken for a UV filter.

It's also possible that the REAR optical element might have been loosened or miss-adjusted.

H2

[stevebrot]

It's also possible that the REAR optical element might have been loosened or miss-adjusted.

...or even missing! A lens that fails that badly at infinity focus is not out of adjustment. Something is no longer there that should have been.


Steve

[voyager13]

Arjay Bee - That Brian Ayling page is beginning to look like a good idea to me Its the crisp focus the 50/1.4 does at its normal 17" distance that is keeping me from sending it to lensheaven.

Stevebrot - It makes sense to think perhaps something is missing otherwise why wouldn't it not focus at infinity, but than I am also thinking if something was missing that didn't allow it to focus to infinity than it should also not allow to focus at its normal 17" distance. But again, I do not have an understand of what it takes to construct a lens so perhaps the lens is missing something after all. How to know what may be missing?

[stevebrot]

Stevebrot - It makes sense to think perhaps something is missing otherwise why wouldn't it not focus at infinity, but than I am also thinking if something was missing that didn't allow it to focus to infinity than it should also not allow to focus at its normal 17" distance. But again, I do not have an understand of what it takes to construct a lens so perhaps the lens is missing something after all. How to know what may be missing?

Your lens may have been scavenged for parts at some point. A missing rear element is a possibility.


Steve

[siamthai]

I now know what it the problem was. The lens had some kind of extra m42 screwmount that was mounted, at first I wondered what it was and then I realized that it was a short macro extension tube that someone forgot to remove. In fact it's the shortest I've ever seen, only about 6 mm.

Anyway, I removed it and now the lens works as it should.

[voyager13]

Anyway, I removed it and now it works as it should.

Christmas has come early to you than Enjoy.
Good to know it has gone to someone who would keep it well

[siamthai]

Christmas has come early to you than Enjoy.
Good to know it has gone to someone who would keep it well

Thanks Voyager13, it's a beatiful lens (and as new). It's now mounted on my K-5

[Arjay Bee]

someone who would keep it well

If a pic or two had been posted in the first instance then this lens would probably still be in your possession - glad you didn't use the Brian Ayling technique to rectify the issue however.

[voyager13]

No regrets Arjay Bee. The lens has gone to a Pentax-loving person and I am happy about that. We are a big Pentax family here