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03-12-2011, 04:57 PM   #1
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Any idea on what kind of filter this is? (Soviet made)

I have a Soviet made 500mm mirror lens that came with four filters, three of them are easy to figure out.

One is amber, one is green, and one is gray.

The fourth is the one I am not 100% sure of, its clear so my guess is that its a UV haze filter but sometimes its better to ask.

There does not seem to be a brand name on the lens, but it does have what I guess is a brand mark/symbol. A lower case 'c', inside a triangle, inside a circle.

The only marks on the filter are:

*CIO <the_brand_mark> 77x0,75

So am I correct in thinking that its a UV haze filter, or is it something else?
Possibly just a piece of glass to help protect the lens?

Or a super secret filter used to view invisible inks on KGB documents?
It was made during the 'Cold War' (1979) <---

03-12-2011, 06:02 PM   #2
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Yep, it's a UV filter. Many mirror lenses have a small filter holder near in the rear of the lens. They are 30.5mm or 43mm in some cases, much cheaper than a 100mm job up front. They usually recommended having one in place, so the UV was the most common. With digital cameras, the only useful ones are the ND (gray one) tp allow slower shutter speeds in bright light, and a polarizer (normally up front) to control reflections or more often, darken blue sky.

Last edited by SpecialK; 03-12-2011 at 06:08 PM.
03-12-2011, 08:34 PM   #3
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Based on your description of the logo, the filters were made by LZOS in Russia. That concern is responsible for many excellent optics including the cult classic Jupiter-9 85/2 and very capable Jupiter-12 35/2.8 (unfortunately a rangefinder only lens).

As you use the lens, you may want to try it both with and without the clear filter. Some FSU lens designs that use rear-mounted filters (e.g. Zenitar 16/2.8 Fisheye) require the filter as part of the optical path and yield degraded results without them.


BTW...the lowercase "c" in the logo is the Cyrillic equivalent of the Latin "s"
03-12-2011, 09:50 PM   #4
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Thanks for the confirmation and the info.

Just to let you know these filters actually go on the front of the lens, they are big 77mm monsters.

Looking at the lens there are some threads at the rear but the optics of the lens doesn't leave much room to mount anything there.
Plus the case the lens came in has a dedicated space for these front filters but no spot for any smaller filters so I think I can say it doesn't need the rear mounted ones.


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