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Old Feb 16, 2010, 9:00 PM   #1
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Default Question on Vivitar Series 1 Catadioptric 600mm lens

The lens made by Perkin Elmer. I've read that it must have a filter mounted at the mount end before the optical formula is complete. Is this so? And if it is so and someone has a lens of this type but no filter....where can you get one? If purchasing a filter is out of the question ,,,then can one be made to fit the lens?

I'm asking because I'd like to buy one but there is no mention of a filter in the Ad. I've sent a question to the seller asking if the filters come with the lens but I am not sure they know enough to be capable of looking or will even look. Any help would be nice. Thanks in advance.
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Old Feb 17, 2010, 2:43 AM   #2
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according to Roger Hicks and Frances Shulz in The Lens Book cats designed with provision for rear filters must have one fitted, even if it is an only a relatively clear UV filter.
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Old Feb 17, 2010, 3:24 PM   #3
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The only reason I could imagine for this would be when shooting film, which is more sensitive to UV. Since there are fewer optical elements or filtering in the lens itself, the filter may be more needed for film. Not very likely to make a difference for digital, though.

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Old Feb 17, 2010, 9:34 PM   #4
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Thanks guys. From what has been told me buy some on another forum...the difference is in the register distance between the rear lens element and the sensor or film plane. The filter adds just enough thickness to help the lens reach infinity focus and give a sharper photo.
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Old Feb 17, 2010, 11:48 PM   #5
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The filter isn't adding any distance optically. Sounds to me like they either don't know what they are talking about or they is putting you on. The filter doesn't modifiy the optics.
I do have a 800mm cat that I had to do some machining on the T-mount in order to bring the rear lens element closer to the film plane (sensor) on my *istD, as it wasn't making infinity focus. Only other way would be to adjust the internals of the lens.
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Old Feb 18, 2010, 4:10 PM   #6
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To quote from the OEM Maxxum AF Reflex 500mm manual "To obtain optimum results, one of these filters should be used at all times, since the filter is an integral part of the lens' optical design." Maxxum, Sigma Filtermatic, and Tamron Adaptall SP mirrors all come with a clear filter installed, plus one or more additional filters.
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Old Feb 18, 2010, 8:23 PM   #7
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Then it's not just a filter. Or, as I mentioned, since the maxxum is a film camera ....


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Old Feb 18, 2010, 11:11 PM   #8
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Quote:
Originally Posted by VTphotog View Post
Then it's not just a filter. Or, as I mentioned, since the maxxum is a film camera ....


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Call it what you will, they still want glass there - and the same lens is still sold by Sony, unchanged as far as I know (except for the name) for the alpha digitals, and the old one works just as will on my alphas as it did on my Maxxum film cameras. I am not challenging you, or arguing the optics, just telling Dawg what the manufacturers say and do, in answer to his question.
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Old Feb 22, 2010, 2:20 AM   #9
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Welllll, if you do not have a filter in there (on some lenses) there is a hole in the side for light to get in!
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Old Feb 22, 2010, 7:54 AM   #10
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Quote:
Originally Posted by John Hill View Post
Welllll, if you do not have a filter in there (on some lenses) there is a hole in the side for light to get in!

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