"Bleaching" a yellowed Pancolar ?

[japomono]

Has has anybody succeeded in "bleaching" a first generation M42 Pancolar 50/1.8 ?

I have such a Zebra lens, which is very yellow. As opposed to the 50/1.4 Takumar, it seems all elements are yellow, or at least it is yellow in front and behind the iris.

I tried to expose it to a UV lamp, but it does not seem to do much. Has anybody a more positive experience ?

[Brian]

I've had luck with the Takumar and a Summicron with a UV lamp. Days of exposure was required. I received a Summicron that was sunbleached. It required a lube job, the heat of the Sun baked the original lubricants.

[estudleon]

Hi. The zebra pancolar (F/2 or F/1,8) is one of the more yellowish 50 mm lens. But it's yellowish by itself, the UV reduce only a few the color cast.

The pancolar 1,4/55 is another example of this theme.

Did you find your pics exessively yellowish ? If not, if the IQ isn't affected, let it be like it is now. Excuse me, not help you but it's more easy. :)

Seriously, you can expose the lens to the sun one or two month.

Rino.

[japomono]

OK ! Indeed, the Takumar I also received recently is much less yellow and seems to slowly bleach in the UV light. And the slightly warm rendering is fun.

In the case of the Pancolar, I found the coloring really quite strong and I had the feeling the coloring was eating up some light. I do not know if it actually did bleach somehow in the last week, but I checked and it is about 1/3 to 1/2 of a top darker than other 1.8 lenses. Apart from that, it is a great lens.

I'll wait some more days and re-check.

Here is a pic made with the Pancolar on film:

<a href="http://www.flickr.com/photos/bw94/4415353106/" title="zum 1. Mai by BeWePa, on Flickr"><img src="http://farm5.static.flickr.com/4050/4415353106_4cf7da8f67.jpg" width="500" height="336" alt="zum 1. Mai" /></a>

[kds315]

Which UV lamp would be good for that - one used for tanning?