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

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