Re: Koehler illumination in conoscopic observation

Kevin Cunningham wrote:
<snip>


A ground glass filter should be used, I'll bet there is a place for
one. Other wise I'd put it close to the lamp, if possible directly in
front of the lamp. Then, technically, your using critical
illumination, not Kohler but who cares?

I don't think that's correct- critical illumination is the Fourier transform of Kohler illumination: the filament is focused onto the sample plane rather than the entrance pupil of the condenser. And actually- that's the better solution.

Using a ground glass plate is a kludge to destroy the image of the filament in the back aperture of the objective lens; it may work, but it isn't critical illumination.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University
.

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