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  1. #31
    benjiboy's Avatar
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    Quote Originally Posted by fenderslash View Post
    Thanks uncle Ben

    I suppose the main thing I can contribute to the thread is that I've proven that it doesn't have to be that particular Ikea lamp. All similar LED lamps probably work fine.
    True, but the Ikea Jansjo lamp cleared the yellow caste from my Canon FD 35mm F2 Thorium lens in forty eight hours, and it makes a very useful reading lamp afterwards.
    Ben

  2. #32

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    Quote Originally Posted by benjiboy View Post
    True, but the Ikea Jansjo lamp cleared the yellow caste from my Canon FD 35mm F2 Thorium lens in forty eight hours, and it makes a very useful reading lamp afterwards.
    I was struggling to find an appropriate UV source.

    Here in LA finding the sun is no problem. But it has been a tad cloudy lately.

    Then I remembered a light fixture I have for video production. Ta-da!

    The TruColor HS is a remote phosphor LED source that uses panels of phosphor excited by purely UV LEDs.

    With the panels removed, 400W of UV light is bearing down on my lenses.

    Any guesses how long it'll take to remove the yellowing? A day or two? 20 minutes?

    Click image for larger version. 

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  3. #33
    digital&film's Avatar
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    I got the Ikea light (from Amazon) and the yellowed Takumar 50mm 1.4 is near perfectly clear!

    Damn.. a few days (and nights) with the light and it cleared up a lens that was yellowed to the point of 1.3 stops!

    Thank you for whomever discovered this.
    Robert Brandoff

    "Fauxtographer with a faux sale of a Fauxtoshopped fauxny image."

    My man, Drew.

    www.digitalandfilm.com

  4. #34

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    I will look for the Ikea lamp because I have a 28/2.5 MC Rokkor-X which is being serviced. Like my older MC Rokkor, it has darkened. I think the problem element is in a rear group. When the MC Rokkor-X comes back I will want to work on it. My earlier experience is with a 35/2 Canon FD SSC (1st version). That lens was kept under a CFL bulb with aluminum foil under it. It pretty much cleared the lens but took about five months. I later got another 35/2 FD SSC (2nd version) which is also a very good lens but which has no color problem. If I read the diagrams on the Canon Camera Museum website correctly the optical formula looks like that of the later 35/2 New FD, also a very good lens.

  5. #35
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    Quote Originally Posted by zenrhino View Post
    Hi,

    I have a yellowed SMC Takumar in M42 for my Spotmatic. I love the lens for b/w, but I want to shoot color with it and I find the yellowing drops probably a full half-stop from getting through the viewfinder (which at my age is increasingly a problem).

    I could just set it out in the sun as such: http://www.apug.org/forums/archive/i...p/t-41848.html

    But, is there a better/faster way to get UV on it?

    Thanks,

    Clint
    afacetanner will do a nice job.the window sill may take months
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  6. #36

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    The IKEA lamp arrived yesterday and I picked up the 28/2.5 MC Rokkor-X this morning. Later today I will set everything up and see what happens. The lamp looks like it will be handy for other things too.

  7. #37

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    The aluminum foil is under the front of the lens and the lamp is about half an inch from the bottom of the lens. If this works I will find my older 28/2.5 MC Rokkor and give it the treatment too.

  8. #38
    Zathras's Avatar
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    Quote Originally Posted by dynachrome View Post
    The aluminum foil is under the front of the lens and the lamp is about half an inch from the bottom of the lens. If this works I will find my older 28/2.5 MC Rokkor and give it the treatment too.
    Be sure to let us know how it works. I'm thinking of getting one of these to clean up a couple of yellowed Takumars.
    When the chips are down,

    The buffalo is empty!!!



  9. #39

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    About four hours to go for the 48 hour look.

  10. #40

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    After 48 hours under the lamp the 28/2.5 MC Rokkor-X is tremendously improved. There is a very faint cast left. Nothing like the dark yellow/green cast it started with. I compared it to a 28/2.8 MD and a 28/2.8 MD Celtic (last version). I've decided to put the lens back under the lamp for another two days and look at it again then. Now I can find the 28/2.5 MC Rokkor.

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