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06-08-2009, 04:50 PM   #1
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Screwmount and KMount Booty

So my girlfriend called me this weekend saying she found a bunch of old lenses in a thrift shop. I asked her what they were, and turns out they were a Takumar 135mm 3.5, an Auto-Takumar 35mm 3.5, and an SMC Pentax 50 1.7. All for $10.

They were in a pretty fowl camera bag, and the focus rings are VERY tight. Any tips on cleaning them up? I probably won't use them for any serious work unless I can get the immaculately clean. I am planning on using them on my soon to come K1000 and K20d.

Thanks!

06-08-2009, 09:47 PM   #2
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Go to the Manual Focus forum...they have a section on fixing old lenses. Hope it helps you......
06-09-2009, 05:31 AM   #3
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Meanwhile, you can excercise your lens focusing muscles by repeatedly turning the focus rings, as this sometimes loosens them
06-09-2009, 05:58 AM   #4
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keep in mind that Takumars, well manual focus lenses in general are suppossed to have a tighter focusing helicoid than an AF lens.

06-09-2009, 07:50 AM   #5
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Based on a foul bag, my biggest concern would be fungi. Obviously ditch the bag and keep those puppies in a dry place.
06-09-2009, 09:46 AM   #6
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Blue,

there is some stringy looking stuff in the lenses. Is that the typical symptom for fungi? If so, how do I get rid of it?

I asked Eric and he said he couldn't work on the Takumars because they are silver and black. Is there anyone that knows how to get rid of the fungi? Are these lenses popular and common enough to have guides somewhere online on how to take them apart and clean them, and get them back together again?

Alternatively, are these lenses not worth much and I shouldn't bother working on them?

Thanks!
06-09-2009, 09:54 AM   #7
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QuoteQuote:
there is some stringy looking stuff in the lenses. Is that the typical symptom for fungi?
sounds like fungi to me. if its still alive and spreading, UV light will kill it. but the damage may already be done. if the fungi has etched the glass where it has been in contact then you will have a permanent haze. I don't know anyone in particular who can disassemble and clean them. this of course doesn't mean they are completely unusable. on the contrary, but they may not be worth the price or effort.
06-09-2009, 12:56 PM   #8
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You could probably sell the lot on eBay for way more than $10, even disclosing the problems. The lenses are worth repairing but probably not worth paying someone to repair. It's cheaper to buy ones in better condition. The Auto-Takumar 35mm f3.5 is an exception, not nearly as common. Just the experience you can get working on one of these lenses can save you a lot if you buy more old lenses.

I started to put together an article on disassembling one of these, the SMC Pentax-M 50mm f1.7. Here is the photo album that I put together.

Picasa Web Albums - David - Disassembly

I lost the four pages of text that went with it and still haven't rewritten it. The basic idea for almost all Pentax or Takumar lenses is similar. Use some kind of friction tool to unscrew the "name" ring, the trim piece inside the filter threads with the lens info on it. That gives you access to screws and more rings holding the lens elements together. From the back of the M50/1.7, simply removing the mount gives you enough room to unscrew the rear lens group by hand. Takumars are more difficult from the back, sometimes completely solid.

Once you get access to the lens surfaces, a good cleaning will help. I just use Windex, whick seems to be strong enough to kill the fungus and clean the lenses. Look carefully at the lens surfaces to see if the fungi has etched them; unfortunately it's impossible to fix this damage. I often wipe down other surfaces inside the lens but there are probably fungi spores everywhere that are impossible to get to. Keep the lenses in a bone-dry environment for a while and check often for regrowth.

I have never had to fix the focus rings on a Pentax or Takumar; just turning them has freed them up. It might help to leave them in a sunny window for a day. The warmth will help loosen the focus grease.

Someone mentioned this site with no link. There is plenty of repair info here:

Manual Focus Forum

06-09-2009, 05:32 PM   #9
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These MF lenses shouldn't be tighter than AF lenses. I would say that they are "dampened". In fact most MF lenses focuses really smooth, especially the takumars which focuses like cutting butter.
06-09-2009, 07:32 PM   #10
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After playing with the 135, it has loosened considerably. It feels like a manual focus lens should. Also, it has the least amount of fungus as all the lenses. That's great news because it's a very useful focal length for the kind of stuff I tend to shoot most often. Too bad it doesn't focus closely.

The 35mm lens doesn't have an aperture ring (or at least, it's gummed up so badly it doesn't turn), so how does it work on a camera? Do you just always shoot it wide open?

The 50 1.7 is by far the worst in terms of fungus. I don't know if I'll spend the time and effort to clean it up. If I do a good job on the 135 and 35mm I'll probably try it, but right now I'll probably get the current 1.4 so I can use Autofocus. I don't trust AF fully, but I tend to get a higher percentage of keepers when using a shallow DoF, like at 1.8 or 1.4.
06-09-2009, 08:15 PM   #11
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QuoteOriginally posted by brofkand Quote
The 35mm lens doesn't have an aperture ring (or at least, it's gummed up so badly it doesn't turn), so how does it work on a camera? Do you just always shoot it wide open?

The 50 1.7 is by far the worst in terms of fungus. I don't know if I'll spend the time and effort to clean it up. If I do a good job on the 135 and 35mm I'll probably try it, but right now I'll probably get the current 1.4 so I can use Autofocus. I don't trust AF fully, but I tend to get a higher percentage of keepers when using a shallow DoF, like at 1.8 or 1.4.
If it's stuck wide open, then you'll have to use it wide open all the time. OUt of curiosity... does it have the auto-manual switch?

Consider the split screens like the Katzeye or the chinese ebay ones if you don't have them already
06-09-2009, 08:16 PM   #12
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If I remember right, it's possible to get the rear lens group out of the Super-Takumar or later models with just a lens spanner or substitute tool that fits in the small square slots. If your fungus is in the rear group, it might be easy to clean. The minimum focus distance is the bane of most of the Pentax or Takumar 135s.

The Auto-Takumars have a cocking lever mechanism that sets the aperture. I forget exactly how this works but it may be your problem.
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