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Old Apr 25, 2003, 6:48 AM   #1
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Default Vignetting

I use an EagleEye L1 adapter to connect my CP4500 to my Leica 32WW eyepiece. While I'm generally happy with the results I do see some vignetting on this set-up (although removing the rubber eyecap from the eyepiece has helped enormously) and I'm looking for some advice as a result.

My understanding is that with a 77 millimetre objective and a 32X eyepiece I have a 2.4 millimetre exit pupil, and that this relationship would hold true for other objective size/magnification combinations.

I also understand that my Nikon has an "unzoomed" focal length of 8 millimetres and a base f ratio of 2.7, giving a camera aperture of 3 millimetres.

Hence a 0.6 millimetre difference and thus vignetting.

Am I correct in thinking that my options are -

1) Find a 25X eyepiece for the Leica to bring it in line with the camera. If so, where could I get one ?

2) Wait until Leica or Swarovski come up with a 100 millimetre objective (and then if its a Leica try and find the strength to carry it !)

Or is there a clever f stop rabbit I can pull out of the hat ?
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Old Apr 26, 2003, 7:52 PM   #2
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Hi Graham,

I believe either there are one or more companies which make adapters which retrofit the Leica to use 1.25" astro-type eyepieces. Look on the web and I believe you will find one for much less than the super high price Leica use to get for their own.

You can then get several eyepieces such as the William Optics 24mm (DCL-28), or one of the several which are made by ScopeTronix like the 18mm, etc. These work well with the Leica and give you about 90 percent of the full zoom range on your camera. Also they screw directly to the 28mm threads so you can dispense with using the mechanical adapter. This gets you even closer to the eyepiece.

Lin
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