[JoelA]

All,

My Tele-takumar 300mm F/6.3 (early version with the front preset dual ring) has come apart.

Literally.

The front section of the lens which has all of the elements in it, has unscrewed itself from the base.

Logic would have it that simply screwing it back in would solve the problem. Alas, when I do that, then the focus ring won't move. If I set it so that I can get the focus ring to move, then I can't screw the element housing back in.

I've taken the one larger screw out of the back housing, but that did not change things.

There's a fair amount of oil going on also, which leads me to think this old lens had a good CLA somewhere along the line. It would focus well out past infinity also.

I only paid $60 for it, so I'm not looking to dump a ton of money into it (and someone on the forum here sold me another m42 lens for $20 - so I'm covered that way).

It's more about the challenge. I'm pretty mechanically inclined - and have to be missing something really simple!

Any help would be super appreciated!

Best,

JoelA

[marcusBMG]

It would focus well out past infinity also.

A clear indication of previous misassembly.
A lot of these older lenses have a focus assembly with a rail or pair of rails that hold one side of the helicoid. You probably need to do something like back track the focus sleeve, then engage the end in the thread and turn the sleeve to wind it in. Trial and error to get the right engagement point so it all gets back to as it should be.
Correct disassembly: should have counted the turns, marked the separation point etc.
You're not the only one. I have a tamron adaptall 4B 200mm with a double helicoid: coarse and fine threads that are both actioned by the turning of the focus. Now that its in pieces I can see how it works and what I should have done while disassembling

Persevere...

[biz-engineer]

Any help would be super appreciated!

I had an old tele-converter sold to me for $10, I tried it, there was a problem with the aperture lever, I looked at it see if I could fix it, I couldn't. So I decided to throw it together with house rubbish, as it would have costed me more to return it to the seller. I took my credit card out of the wallet, ordered an HD TC x1.4 new from Ricoh, received it, opened the box, mounted on the camera and it worked. Problem solved.

So, my advice would be to dispose your 300 f6.3 in the rubbish or use it as paper weight or cup holder, and buy a Pentax HD DA 55-300 PLM or D-FA 70-210 f4 (even a used one), it's going to work immediately, focus automatically silently and quickly, offer a versatile zoom range and deliver top notch no flare no ghosting images (especially compared to a Tak 300 f6.3) right out of the box.

[Bob 256]

The Pentax lens disassembly database lists this reference for the 300mm F6.3 - might be worth a check if you want to keep this lens.

JB Media | Tele-Takumar 6.3 300mm

[JoelA]

Many thanks for the ideas!

The house is quiet, coffee is brewed, and I'm bound and determined!

I'll report back.

[TwoUptons]

Good Luck! That's a pretty neat lens.
I think the preset works well with it -- you can focus wide open then close it down quick to expose.
I've also been pleasurably surprised at how little CA it has.

-Eric

[Arjay Bee]

I had one of those and was quite happy with it. I can understand the urge - there is a sense of achievement for me when a non functioning piece of equipment can be resurrected that is disproportionate to the value of the item. I look forward to a progress report.

[yucatanPentax]

Sorry I don't have specific advice on that particular lens (I'd like to have one though!), but just words of encouragement. I really like the results from preset lenses so I hope you can sort out the issues. The first couple of comments have some good advice. Getting the focus threads right should allow the pieces to be threaded together again.

Excess oil should be removed, but a bit of oil on the aperture blades of a preset lens are not too much of an issue. (The worse issue is "fumes" from extra oil evaporating in the heat or sun, then depositing on internal lenses, leading to some haze on the lens, which is why I might try to remove any excess amounts.

Good luck! Let us know what you find.

*just a quick edit to say, I disagree so much with the "trash it" viewpoint. I like trying to fix things and what's the harm in trying? This is a unique lens from a by-gone era which may deliver a special look to your images. Cheers!

[JoelA]

Success!

Thanks for the hints helicoid/rails, the photo links and the words of encouragement, they were quite helpful.

Ok, here's what I did. So in looking at all of the pictures and thinking about what marcusBMG said, I figured that I really needed to work on a flat surface to get the parts to line up properly. If you look at the link that Bob 256 provided, the situation was exactly as shown on the last slide of the first page - the lens in two large pieces. Got out a level (there's one on an iphone) and made sure things were flat. Then took a K-50 camera with a Pentax branded K->M42 adapter and set it up side down, resting on the rear viewing screen (to keep it flat). I then screwed the (back) part of the lens in that has the focus mount - and checked for level again. Now the fun started. Using the weight of the (front) of the lens (remember all the elements are in the very front on this lens), started placing it on to see if I could get the main screw to engage back into the brass fitting (see the second to last picture on the assembley link). Amazingly it went together in about 5 minutes! Just screwed right back in place. And stayed there!

The lens focusses near and far just fine now. The distance ring was not set in the right place, so that does not match the actual distance, but honestly I never look at the focus distance on the ring anyway. I probably could reverse the process and set the ring first, but I don't DARE take it apart on purpose now that it's back together! It still focusses a bit past infinity, which I guess is reassuing me that the elements didn't get (more) messed up in the process.

And to those of you who are wondering why...why...why to spend the time on a such an old slow lens - great question! - well, here you go!

First, the process of compostion, f stop selection, shutter speed selection is what I really enjoy in photography. It's darn near theraputic. This lens demands that, and it's something I enjoy.

Second, I live in Orlando, Florida USA - Disney, Kennedy Space Center etc. There's a TON of light here. It's always super bright, really bright. So, a f/6.3 lens is never an issue. And this lens is amazingly light weight, and super well balanced. It ends up being a wonderful walk-around everyday 300mm lens. It just super easy to carry and like I said, there's tons of light and honestly very little flare or CA even in broad daylight when using the lens hood.

This one earns its place in the camera bag!

Many thanks!

JoelA

[ramseybuckeye]

Success!

Thanks for the hints helicoid/rails, the photo links and the words of encouragement, they were quite helpful.

Ok, here's what I did. So in looking at all of the pictures and thinking about what marcusBMG said, I figured that I really needed to work on a flat surface to get the parts to line up properly. If you look at the link that Bob 256 provided, the situation was exactly as shown on the last slide of the first page - the lens in two large pieces. Got out a level (there's one on an iphone) and made sure things were flat. Then took a K-50 camera with a Pentax branded K->M42 adapter and set it up side down, resting on the rear viewing screen (to keep it flat). I then screwed the (back) part of the lens in that has the focus mount - and checked for level again. Now the fun started. Using the weight of the (front) of the lens (remember all the elements are in the very front on this lens), started placing it on to see if I could get the main screw to engage back into the brass fitting (see the second to last picture on the assembley link). Amazingly it went together in about 5 minutes! Just screwed right back in place. And stayed there!

The lens focusses near and far just fine now. The distance ring was not set in the right place, so that does not match the actual distance, but honestly I never look at the focus distance on the ring anyway. I probably could reverse the process and set the ring first, but I don't DARE take it apart on purpose now that it's back together! It still focusses a bit past infinity, which I guess is reassuing me that the elements didn't get (more) messed up in the process.

And to those of you who are wondering why...why...why to spend the time on a such an old slow lens - great question! - well, here you go!

First, the process of compostion, f stop selection, shutter speed selection is what I really enjoy in photography. It's darn near theraputic. This lens demands that, and it's something I enjoy.

Second, I live in Orlando, Florida USA - Disney, Kennedy Space Center etc. There's a TON of light here. It's always super bright, really bright. So, a f6/3 lens is never an issue. And this lens is amazingly light weight, and super well balanced. It ends up being a wonderful walk-around everyday 300mm lens. It just super easy to carry and like I said, there's tons of light and honestly very little flare or CA even in broad daylight when using the lens hood.

This one earns its place in the camera bag!

Many thanks!

JoelA

Well done! Now some sample photos!

[marcusBMG]

Good job

[Arjay Bee]

Well done.

I also live in the tropics so the f6.3 was not an issue. The lens demanded a bit of a stepped process to use but the images it produced were unique.

[yucatanPentax]

Wow, Congrats on your success! Maybe a pic or two when you have time? Either taken with the lens, of the lens itself, or both!
Thank you, also, for sharing your assembly technique. Frequently such explanations help others.

[espirit]

Hello friends, I'm from Brazil, I got a very new copy of this lens, with case, cover and hood, but it has fungus, the link provided above no longer exists, I would be very grateful if anyone could help by giving a disassembly tip to access the glasses of this lens, through the front rim, access only to the first element, from what I understood reading the conversation, I imagine having to release the focus rim and from there maybe be able to disassemble other parts? from the rear also doesn't give me any access to the rear assembly. Thanks for any help.