Heine Condenser and Kohler illumination

[MikeBradley]

I am learning to use a Heine Condenser on an Olympus BH2 with a custom adapter. I can centre it using the internal phase ring as a guide and the results it delivers have been quite good in DF and BF. However I can’t find a setting of either the condenser height or the Heine internal optics adjustment where the leaves of the Field diaphragm are in sharp focus and this makes me think that the illumination may be far from optimal. I was wondering what other peoples experience with the Heine have been and how they align it?
Thanks
Michael

[Brad_]

Hello Michael,
The Heine condenser isn't made to use a field iris or Kohler illumination.

Just keep your iris wide open and you'll be OK.

Have fun.

Brad

[MikeBradley]

Brad, thanks for the reply. I had believed that the sharply focused field iris step in the Kohler procedure was especially important when setting up "regular" phase contrast, and that would apply even with the unusual light paths of the Heine. I live and learn!
Thanks
Michael

[75RR]

Found this, thought it might be of interest: http://www.science-info.net/docs/leitz/LeitzHeine.pdf

[MikeBradley]

Thanks, I very much for this link, Ihad not seen this publication before, only the Leitz Heine Manual.
Michael

[Brad_]

Hello Michael,

Sorry for having been so terse in my reply. I was a bit busy.
Here's a little more info.

Leitz offered the Heine condenser early on in the development of
the Ortholux, perhaps even in 1937. It's hard to believe but
the early Ortholuxes were sold without even a provision for a
field iris. Judging only from what's available on eBay, they
sold a lot of them. I'd like to know when the field iris was
first offered. Probably decades after Zeiss discovered this
necessity.

I have in my junk box a mundane Leitz 40x from the early 1960s
that requires very careful setting of Kohler to eliminate a hot
spot in the middle of the field. I just tried it with the Heine
and no hot spot, if that means anything.

Have fun.

Brad