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That's a great tip!  Thanks!  We actually have one completly homebrew
rig, and two heavily modifed Nikons for multiphoton.  We use our own
telescopes and scan lenses at the input port to size our incident beam
such that the objective apertures are filled.  I had no idea that it
was such a problem in off-the-shelf units though!

Craig


On 9/5/07, Stephen Cody <[log in to unmask]> wrote:
> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> G'day Graig,
>
> If I may answer a question you haven't asked!....
>
> Before making a decision on a dipping lens (presumably you are going to
> purchase a whole new confocal / multiphoton to go with that lens), you
> should ask all the manufactures to report what percentage of the back
> focal plane of the dipping lens is filled. Ask for a report from the
> factory (don't rely on a response of the sales team on this one, they
> are not likely to be aware). Also let them know that it is easy enough
> for you to test, that way you will receive a frank response.
>
> Many of these High NA, Low magnification dipping lenses are drastically
> under filled. Hence they are only operating at a fraction of the
> nominated NA unless installed on the physiology microscopes for which
> they were developed. Unless we ask the manufacturers to do something
> about that nothing will change.
>
> If a 20x dipping lens and a 60x dipping lens are marked with the same
> NA, then the 20X lens used with an optical zoom of 3 should perform
> similarly to the 60x lens at a zoom of 1. This would be of benefit for
> live cell experiments as you could use low power to find the cells of
> interest and then simply zoom in for high resolution images.
>
> However, I believe in most installations the high NA 20x dipping lenses
> are under filled and so this strategy does not usually work.
>
> Cheers
>
> Stephen H. Cody
> Microscopy Manager
> Central Resource for Advanced Microscopy
> Ludwig Institute for Cancer Research
> PO Box 2008 Royal Melbourne Hospital
> Parkville, Victoria,      3050
> Australia
> Tel: 61 3 9341 3155    Fax: 61 3 9341 3104
> email: [log in to unmask]
> www.ludwig.edu.au/labs/confocal.html
> www.ludwig.edu.au/confocal
>
>
>
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