Re: Recommended Zeiss Objective Sets


"GTO" <gregor_o@xxxxxxxxxxxxxxx> wrote in message
news:9zjWg.10952$e66.8401@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Your statement "... because dark field is useless" is incorrect.

In material research, EPI darkfield is very often used. For my work, I use
it frequently. BTW, diascopic DF is highly recommended for serious
amateurs. Of course, one must work carefully to obtain good results. So,
DF is not recommended for everybody playing with a scope.

Cheers,

Gregor


Sorry, I should have been more careful. Reflected darkfield is a very
different bird, it works well. On the other hand transmitted darkfield just
plain isn't as workable as DIC and phase. Transmitted darkfield doesn't
have the NA that the other two techniques have.

Here's another way to look at it. None of my customers use transmitted
darkfield. None. In the mid-eighties some neurologists used very low power
dark field for certain irradiated slides but that soon ended. From '82 to
'89 the dealership I worked for (3rd in America) sold 3, all dry, low power.
In the last 16 years I saw one sold, again, dry, low power. Now, -0-. I'm
sure their a lot of fun to mess around with but they just don't have any
practical uses.

Thanks for pointing out my error.

Kevin Cunningham
SMS
There are no objectives for dark field because dark field is useless.
Zeiss objectives come in phase flavor and they work well for bright
field. If you want real live pol, Zeiss makes pol objectives but check
them carefully, the centering mechanism might have some problems with
age. You'll also need a pol nosepiece and condenser.

DIC has to have plan lenses, either Plan Achromats, Flourites or Apos.
Then you have to get the accesories such as a condenser, intermediate
pieces, appropriate sliders and polarizer.

Good luck!!!

Kevin Cunningham
SMS





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