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Date: | Fri, 21 Feb 1997 11:10:04 +0100 |
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In answer to the following letter by Paul Goodwin:
>
Good morning,
I fear there is a misunderstandment about the general characteristics of water
immersion lenses made for use with coverslips.
> It is definitely different from phenlyene diamine. It is glycerol based
> with a r.i. of 1.4 something. If you are using a water immersion lens that
> is made for use with a coverslip, it assumes that the sample is in
> glycerol, even if the immersion liquid is water.
I am quoting from http://www.zeiss.de/mi/limi_e/p8/capo_e.html :
"
...
For the design of water objectives, the refractive index 1.33 for
immersion and mounting is assumed.
...
"
This www-page is describing the C-Apochromat lenses 40X/1.2W Korr and
63X/1.2W Korr by Zeiss. One of the reasons why these lenses were made
is that the image quality dramatically decreases if oil-immersion lenses
are used on objectives in watery solution. These C-Apochromats, which exist
in modified forms even as non-coverslip lenses for the application in
electrophysiology, are made for a substance with the refractive index
close to water as immersion-medium and mounting-medium. A correction collar
can be used to correct for slight mismatches in thickness of cover-slip and/or
mismatches in refractive index, when e.g. using physiological salt solution
instead of distilled water.
Another type of objectives are the multi-immersion lenses which are designed
and built to be used with different immersion and/or mounting media and with
or without cover-slip. Examples of these lenses are presented in, e.g.,
http://www.zeiss.de/mi/limi_e/p8/multi_e.html
and
http://www.zeiss.de/mi/limi_e/p8/l_pn_e.html#multi
.
I suppose that these facts also are valid for Nikon lenses as presented e.g. in
http://www.nikonusa.com/products/biomed/bg/advresearch/e800/accessories/accessories.html#objectives
Best regards,
Paul Johannes Helm
--
I do not have any affiliation to a commercial company. All the information provided
is private information given to the best of my knowledge but without any guarantee
for correctness.
--
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Paul Johannes Helm
Mailadress: Department Physics 4
The Royal Institute of Technology
S-100 44 Stockholm
Sweden
Visitingadress: Department Physics 4
The Royal Institute of Technology
Teknikringen 14/4tr.
S-100 44 Stockholm
Sweden
Voice: +46 8 790 7219
Fax: +46 8 205609
Telex: 11421 kth
WWW: http://www.fysik4.kth.se/~johannes
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