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Old Dec 28, 2007, 4:32 PM   #1
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My Pentax SMC 50mm f/1.4 has accumulated a little dust on its interior after thirty-plus years of use by me. Is it practicable for me to attempt to clean it? I have a nice set of jeweler's screwdrivers if they are needed for the job.

Please don't guess. If you have done that job, I need your help. Or is it better to find a repair shop to work on the lens. It's sorta my baby.

Old Engineer
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Old Dec 28, 2007, 5:53 PM   #2
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i'll post a link in a minute. hopefully i haven't removed it.

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Old Dec 28, 2007, 6:08 PM   #3
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ok OE,
i've done several primes and most primes are the same and it's pretty straight forward.. here's a 50/2 instead of the 50/1.4. they are identical. here's a tutorial i did on this process. you can do it with no special tools so if you run into probs you can ask me here or at roysphoto at gmail.comabout them

you will not be bothering me. just stay alert as to the way the lens are facing when you remove them

DISMANTLE

hope this helps,
roy

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Old Dec 28, 2007, 6:16 PM   #4
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oh. if you have a small suction cup like a throwing kids dart it helps alot. i've got spares if needed. also i work over a clear plastic pan on top of a white bath towel. jack using a jewelers technique sitting down with an apron runiing from his waist to under the table.

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Old Dec 28, 2007, 6:44 PM   #5
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Robar,

That's a great tutorial. I used it recently to clean an old Practicon lense I bought. Not too similar but your instructions were good enough to get me through. Now I have a Praktica 135mm with stuck aparature blades I'm going to tackle next. I need to get an optical spanner, though.

Thanks for the good work!

Slick
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Old Dec 28, 2007, 7:40 PM   #6
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for the spanner you can cut down thin sheet metal. also if the lens itself does not protrude above the slots for the spanner the a straight bladed knife blade works. be careful about anything slipping onto the lens. you screwed up then. these retaining rings are not welded in. i've use just a tough fingernail on many of them. i'm glad it helped just 1 person. that made it worthwhile.

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Old Dec 28, 2007, 7:43 PM   #7
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Slick64 wrote:
Quote:
Robar,

That's a great tutorial. I used it recently to clean an old Practicon lense I bought. Not too similar but your instructions were good enough to get me through. Now I have a Praktica 135mm with stuck aparature blades I'm going to tackle next. I need to get an optical spanner, though.

Thanks for the good work!

Slick
let us know how it works out. i've got my 500/4.5 torn down to having the blades removed. haven't had time or inclination to put it back together..

roy
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Old Dec 28, 2007, 8:46 PM   #8
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Robar, You are just the kind of person, having done the job, that can give us novice tearer-aparters hope for doing things ourselves. Part of the great joy in working with good equipment is the willing helpfulness of those who have climbed the hill before us.

Thanks for the advice. I'll report any complications or successes as I delve into this task.

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Old Dec 28, 2007, 9:55 PM   #9
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OE,
i don't have a set but you really need a full set of JIS screwdrivers.. japanese industrial standard.
also wear latex gloves because of finger oils and use denatured alcohol. i've used acetone but it just drys too fast. also search ebay for ''selvyt'' polishing cloths. they're the best and washable.. i have 3.. these will also make the bodies of your lenses look brand new..

roy
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Old Dec 29, 2007, 6:05 AM   #10
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Hi Roy,
I hadn't seen that tutorial of yours, it's very good, and brought back memories of my first attempt at a Pentax 50/1.7.
I still have the Pentax 135/3.5 that needs a attention to the aperture ring that is somehow fouling, and stopping full rotation of the focus mechanism. Would you know if this lens construction is similar to what you've described in the tut ?.

OE ... the jewellers dodge that Roy mentions is to wear a white apron and pin the bottom edge tautly to the front edge of your bench or desk, if you drop anything you should find it in the apron lap. Be sure you have all you need to hand before you fasten yourself down. ... Jack
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