There seems to be an almost mythical status for the famous 'Heine' Condenser with all sorts of speculation about the cunning magic inside! Well, here's the definitive paper. Not as complex, or as simple as it seems.
https://patents.google.com/patent/US267 ... mann+heine
I don't know if it's been posted here or not, but it's an interesting read. There's a PDF for it as well on the page with detailed info on what and how it does what it does.
The Heine condenser Patent :)
Moderators: rjlittlefield, ChrisR, Chris S., Pau
I have not read that patent word by word, but Paul James' article seemes to cover the most of it:
http://www.microscopy-uk.org.uk/mag/ind ... eine2.html
I had carefully read Paul article twice and almost all other online discussions, as well as did some experiments to see if I could get close to its effect without paying the price, before I purchased the Heine. But I forgot to read the patent. Which is a shame, as I worked in patent prosecution for two years and had been writing/fighting over tech claims.
I bet if you search carefully at USPTO and its international equivalent, you will find the patent for Zeiss pancratic condenser too (though the name may not be "pancratic" - search for "Zeiss phase contrast" to be safe). That one can be bought for as low as $60-90.
http://www.microscopy-uk.org.uk/mag/ind ... eine2.html
I had carefully read Paul article twice and almost all other online discussions, as well as did some experiments to see if I could get close to its effect without paying the price, before I purchased the Heine. But I forgot to read the patent. Which is a shame, as I worked in patent prosecution for two years and had been writing/fighting over tech claims.
I bet if you search carefully at USPTO and its international equivalent, you will find the patent for Zeiss pancratic condenser too (though the name may not be "pancratic" - search for "Zeiss phase contrast" to be safe). That one can be bought for as low as $60-90.
Selling my Canon FD 200mm F/2.8 lens
The funny thing is that the setup I made for the Zeiss appears to give almost the exact effects I see on that page when the condenser is raised and lowered. Same overall look, same effects, same transitional phases etc. It's not an exact 1:1 but it's so close that I don't think I'm missing out.
I did find an iris to travel with the COL stop so now it's more consistent. You can see the annular ring clear as day through the eyepiece opening and it does shrink and grow as the condenser is moved up and down. I'm a happy hamster now!
I did find an iris to travel with the COL stop so now it's more consistent. You can see the annular ring clear as day through the eyepiece opening and it does shrink and grow as the condenser is moved up and down. I'm a happy hamster now!
Gary,
I think when you move a masked collimator lens up and down optical axis, away or closer relative to condenser top pens, the effect will indeed be similar to the Leitz Heine.
Have you tried an 100x NA 1.25 oil immersion objective with your DIY zoom COL? I wonder what range can your illumination ring provide. At high NA and condenser immersion, that range may be limited by the ability of immersion oil to make contact? Dry Abbé condenser won't go over NA 0.9.
Note that the Leitz Heine is an achromatic internal-reflecting cardioid, which is theoretically better corrected. I had never realized how important optical correction is, until I tried extreme oblique/COL and a Heine/apo objectives combo. My achromat objective/Abbé condenser combo, while doing extreme oblique/COL, produced massive blue/purple false color (though they did not make too much false color, when oblique light angle was not extreme), while Heine/apo objective made almost zero false color.
I think when you move a masked collimator lens up and down optical axis, away or closer relative to condenser top pens, the effect will indeed be similar to the Leitz Heine.
Have you tried an 100x NA 1.25 oil immersion objective with your DIY zoom COL? I wonder what range can your illumination ring provide. At high NA and condenser immersion, that range may be limited by the ability of immersion oil to make contact? Dry Abbé condenser won't go over NA 0.9.
Note that the Leitz Heine is an achromatic internal-reflecting cardioid, which is theoretically better corrected. I had never realized how important optical correction is, until I tried extreme oblique/COL and a Heine/apo objectives combo. My achromat objective/Abbé condenser combo, while doing extreme oblique/COL, produced massive blue/purple false color (though they did not make too much false color, when oblique light angle was not extreme), while Heine/apo objective made almost zero false color.
Selling my Canon FD 200mm F/2.8 lens