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01-05-2010, 08:59 PM   #16
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Steve: If you have trouble locating the thread about curing yellowed Takumar 50's and using sunlight to kil fungus, here's the recipe - you needn't buy a blacklight:
  1. Remove both caps
  2. Open the aperture fully
  3. Wrap the lens in aluminum foil, shiny side in, leaving the rear element uncovered. Take care to keep the foil from touching the front element.
  4. Put the lens on a south-facing window sill, angled so the rear element catches mid-day sun directly. Using the rear cap as a support works just fine. The foil keeps some of the sunlight off the black paint, reducing the heat. The foil at the front element reflects the light back through the lens to add another pass of UV.
Clearing a yellowed Tak took me about three weeks. IIRC, kKilling fungus takes a bit longer.

01-05-2010, 09:13 PM   #17
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Um Jake, unless I'm blind as a bat which is not off the cards, there are no screws on the K50 f1.2 focus ring.
Another thought SMC, check the thread the nameplate travels in and see if it is damaged in any way. From memory I can't see how the keeper ring for the front element would interfere with the nameplate unless a previous assembly was seriously botched.
01-05-2010, 11:25 PM   #18
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QuoteOriginally posted by Pentaxor Quote
Steve, I see that you still haven't resolved your lens' issue yet. had you tried bringing or sending it to the Vancam service just here in Vancouver? they say that most of the guys that work there were former Pentax employees or pretty much accustomed to Pentax gears. you might want to give them a ring and try them out. you can call them for free estimates and other matters concerning your lens. here is there website btw >>> VANCAM Service | Contact Us
Thanks Pentaxor....I wasn't aware of them....

QuoteOriginally posted by jake.astig Quote
Steve,
Tell your repair guys to take off the rubber cover on the focusing ring first. There are screws there that you need to take out before you can unscrew the front name ring.

Cheers,
Jake
Thanks Jake but I think he had it off but I can check....

QuoteOriginally posted by Blue Quote
So they are going to charge you for doing nothing?
Hi Blue...I had to pay a fee up front for providing an estimate that they deduct once they do the work. Of course I don't get that fee back but they didn't charge me the rest of the estimate...
01-05-2010, 11:27 PM   #19
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QuoteOriginally posted by monochrome Quote
Steve: If you have trouble locating the thread about curing yellowed Takumar 50's and using sunlight to kil fungus, here's the recipe - you needn't buy a blacklight:
  1. Remove both caps
  2. Open the aperture fully
  3. Wrap the lens in aluminum foil, shiny side in, leaving the rear element uncovered. Take care to keep the foil from touching the front element.
  4. Put the lens on a south-facing window sill, angled so the rear element catches mid-day sun directly. Using the rear cap as a support works just fine. The foil keeps some of the sunlight off the black paint, reducing the heat. The foil at the front element reflects the light back through the lens to add another pass of UV.
Clearing a yellowed Tak took me about three weeks. IIRC, kKilling fungus takes a bit longer.
Thanks Paul...there isn't much sunlight up here this time of year...I'd probably have to wait until summer..

01-05-2010, 11:31 PM   #20
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QuoteOriginally posted by xjjohnno Quote
Um Jake, unless I'm blind as a bat which is not off the cards, there are no screws on the K50 f1.2 focus ring.
Another thought SMC, check the thread the nameplate travels in and see if it is damaged in any way. From memory I can't see how the keeper ring for the front element would interfere with the nameplate unless a previous assembly was seriously botched.
I was wondering about that too....I'll search the internet to see the guts of the 50/1.2 to see how both rings could get fused and what would happen if they twisted together.
01-06-2010, 01:46 AM   #21
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Guys,

You can't unscrew the name ring from the front. I have a K 50mm 1.2 with a mangled name ring because the repair guy used excessive force to unscrew the name ring through the filter thread. He never got it out.

I sent the lens to another guy who I found out used to work for Pentax many years back. He saw the mangled name ring and told me that there are screws on the focusing ring (under the rubber grip) that need to be loosened before you can disassemble the lens.

Good luck.
01-06-2010, 01:52 AM   #22
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Jake, no disrespect inrended but I just looked under the focus ring rubber of my K50 f1.2 and there are no screws there. Perhaps you are thinking of f2 versus the f1.2?
The nameplate will screw off, something I did very recently.
01-06-2010, 02:28 AM   #23
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No worries xjjohnno. We're all trying to figure it out.
Hmmm... I don't have my lens with me so I can't check.
If there's no progress here by Friday, I'll take pics of my lens.
And yeah, it's the 1.2.

01-06-2010, 02:58 AM   #24
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Just checked my notes from the other day SMC, and the front element is kept in place by the name plate, no keeper ring there, the second element has the keeper ring. That's not to say the previous owner had not misplaced/lost the keeper ring for the front element but from memory that first element sits quite cosily inside. I'd had a lot of fun removing the name plate because the lens has a dent in the rim which I had to remove which had also damaged the thread.
01-06-2010, 03:58 AM   #25
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QuoteOriginally posted by xjjohnno Quote
Just checked my notes from the other day SMC, and the front element is kept in place by the name plate, no keeper ring there, the second element has the keeper ring. That's not to say the previous owner had not misplaced/lost the keeper ring for the front element but from memory that first element sits quite cosily inside. I'd had a lot of fun removing the name plate because the lens has a dent in the rim which I had to remove which had also damaged the thread.
A dented filter ring is a very possible cause for the jammed name ring. A dent so tiny, that you don't notice it with your eyes is just enough. I had that with one lens in the past, but could remedy that with a filter thread repair tool (this vice-like screw-in thing, don't know the correct English name).

Ben
01-06-2010, 01:19 PM   #26
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The term I use for that tool is a de-dingifier which is not the correct term. I suppose an expander would be closer to correct as the tool opens out the filter ring and hopefully removes the ding without causing other damage.
01-06-2010, 01:29 PM   #27
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I use this method (Favorite Classics / Filter Ring Dent Removing Tool) to remove filter ring dents and it has always worked perfectly for me. There are few things which can't be fixed with a hammer in the right hands
01-06-2010, 02:27 PM   #28
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Thanks guys. I think he had the rubber grip off and the had the back of the lens apart, so I won't be able to pick it up until next week...
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