My Vanox AH journey (was: Olympus BH-NIC DIC with Nikon CF long-barrel optics?)

viktor j nilsson · Post by **viktor j nilsson** » Thu May 28, 2020 1:22 pm

I posted this over at microbehunter, but I know there are people here with a lot of knowledge so I'll post it here as well.

I have a couple of questions about the older Olympus DIC system that was made for the short-barrel BH microscope in the 1970s.

1) Is it correct that the short-barrel Olympus BH has enough focus travel to accomodate long-barrel DIN objectives?

2) Has anyone tried to use long-barrel objectives from other makers with the Olympus BH NIC DIC system (AH-NA intermediate tube + BH-NC condenser)?

3) Specifically, has anyone tried to set up DIC with Nikon CF objectives on a BH stand?

4) Has anyone tried to use 20x objectives with the 10x or 40x prisms? Did it work OK?

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Scarodactyl · Post by **Scarodactyl** » Thu May 28, 2020 3:20 pm

Not what you're after, but I have used bh2 epi dic prisms with mitutoyo k plan apos (10x and 20x on the 10x and 20x prisms) and gotten what seem like identical results to the intended neo splans. I suspect that if the NAs are close there's a chance it will workm

viktor j nilsson · Post by **viktor j nilsson** » Thu May 28, 2020 3:54 pm

Thanks, Scaro. It is always encouraging to hear examples of working mismatches!

However, I don't think that the NA is as important as the focal length of the objectives and the position of their back focal planes (BFPs).

I know that Zeiss re-designed their objectives when they produced their system with a common objective prism to ensure that they all had BFPs at approximately the same place (which coincides with the location of the objective prism interference fringe).

I've measured the position of the BFP of some of my Nikon objectives, and the 10x and 20x (Fluor, Plan Apo and CFN Plan) have BFP located +-1mm from the beginning of the RMS threads.

My 40x 0.85 Fluor and 60x 0.90 PlanApo, on the other hand, have much deeper BFPs, located 10 and 14mm from the beginning of the RMS thread, respectively.

I am not sure if Olympus specifically designed their short-nosed Plan Achromat objectives to have matching BFP positions. Or, if they simply decided that it was OK to have a ~10mm or so mismatch.

Another unknown to me is if the focal length of say a 10x objective is different in a short-barrel and long-barrel design.

Pau · Post by **Pau** » Fri May 29, 2020 3:10 am

viktor j nilsson wrote:It is always encouraging to hear examples of working mismatches!

Maybe you did see my really mismatched (and more or less working) setup https://www.photomacrography.net/forum/ ... 9260#99260

Playing with the condenser height can help to get DIC in some cases, even if you need to do it outside the ideal Köhler position.

I can't answer your specific questions as I don't have such equipment.
For the #1 I'm almost sure that it can, the CH allows 45mm parfocal objectives although it has an issue: you can set a travel top stage stop but you easily overpass it with the fine focus.

For the other questions...I think that some of them would work, Nikon CFs usually work well with the (highly regulable) PZO DIC and at least few of them with my hybrid system. Of course I can't recommend you expending you money in a so weak and speculative basis

houstontx · Post by **houstontx** » Sat May 30, 2020 8:36 am

If I remember correctly I could obtain the DIC effect with the neo splan oly objectives on the BH DIC system, but the best effect was when the background was a light shade of blue rather than the gray/silver gradient. I was unable to ever obtain the silver background even with the short barrel objectives. I think you drop the stage down to the DIC marking on the focus block? I never used the 20x objective on 10 or 40 (its unfortunate as 20x is really nice to have). I agree about the condenser height adjustment. I never really tried to fine to my BH DIC unit though. I sold it a while back.

I am currently using nikon cf and olympus finite objectives on a reichert zetopan and getting excellent DIC results. I use a 50x leitz objective with the 40x prism, and a apo 60x nikon CF with the 63x prism. Both with great results. I think i get DIC effect with the 50x on both 40x and 63x prism.

I would expect the Nikons to work with the BH DIC, but you may get a blue background at best DIC effect.

dolmadis · Post by **dolmadis** » Sat May 30, 2020 9:23 am

houstontx wrote: I am currently using nikon cf and olympus finite objectives on a reichert zetopan and getting excellent DIC results. I use a 50x leitz objective with the 40x prism, and a apo 60x nikon CF with the 63x prism. Both with great results. I think i get DIC effect with the 50x on both 40x and 63x prism.

I would expect the Nikons to work with the BH DIC, but you may get a blue background at best DIC effect.

Hi,

Very helpful post. I have just completed a refurb on a Zetopan (which I have had for some time) which did not come with DIC. I would be very interested if you could show me a photo of the DIC parts needed and may be some notes which might help me identify these for a search.

Thank you in advance.

BR

John

houstontx · Post by **houstontx** » Sat May 30, 2020 5:19 pm

i have pm'd you with link to photos.

cheers

dolmadis · Post by **dolmadis** » Sat May 30, 2020 11:52 pm

Brilliant Thank you.

The long wait begins...........

John

viktor j nilsson · Post by **viktor j nilsson** » Sun May 31, 2020 6:05 am

Pau wrote:
viktor j nilsson wrote:It is always encouraging to hear examples of working mismatches!
Maybe you did see my really mismatched (and more or less working) setup https://www.photomacrography.net/forum/ ... 9260#99260

Playing with the condenser height can help to get DIC in some cases, even if you need to do it outside the ideal Köhler position.

I can't answer your specific questions as I don't have such equipment.
For the #1 I'm almost sure that it can, the CH allows 45mm parfocal objectives although it has an issue: you can set a travel top stage stop but you easily overpass it with the fine focus.

For the other questions...I think that some of them would work, Nikon CFs usually work well with the (highly regulable) PZO DIC and at least few of them with my hybrid system. Of course I can't recommend you expending you money in a so weak and speculative basis

Thanks, Pau! I have indeed studied both of your threads with great interest many times. I have constructed a somewhat operational DIY DIC system using two identical Nikon epi-DIC prisms. Threads like yours have been very valuable for me in getting it to work. But I'm eyeing an Olympus scope with DIC, as it would undoubtedly be more convenient if it worked. But I'm actually thinking that what I have might be able to give better DIC, as it allows me more control of prism placement, condenser focal length, etc.

viktor j nilsson · Post by **viktor j nilsson** » Sun May 31, 2020 6:11 am

houstontx wrote:If I remember correctly I could obtain the DIC effect with the neo splan oly objectives on the BH DIC system, but the best effect was when the background was a light shade of blue rather than the gray/silver gradient. I was unable to ever obtain the silver background even with the short barrel objectives. I think you drop the stage down to the DIC marking on the focus block? I never used the 20x objective on 10 or 40 (its unfortunate as 20x is really nice to have). I agree about the condenser height adjustment. I never really tried to fine to my BH DIC unit though. I sold it a while back.

I am currently using nikon cf and olympus finite objectives on a reichert zetopan and getting excellent DIC results. I use a 50x leitz objective with the 40x prism, and a apo 60x nikon CF with the 63x prism. Both with great results. I think i get DIC effect with the 50x on both 40x and 63x prism.

I would expect the Nikons to work with the BH DIC, but you may get a blue background at best DIC effect.

Interesting to hear that you didn't get even grey background even with the short-barrel objectives. This makes me think that these objectives may not have been optimized to have their BFPs in the same place as the interference fringe. Rather, the objective prism interference fringe may be located at the "least bad" location, somewhere between the 10x and 40x BFP.

I'm actually getting rather pleasing DIC with even grey background at 10x, 20x and 40x with my current DIY system. I'm not, however, able to get it to be dark-gray at maximum extinction yet, but I'll keep tinkering!

I'll digest your and Pau's comments a but more and get back to you.

Pau · Post by **Pau** » Sun May 31, 2020 9:31 am

Hi Viktor,

Would be nice to see you weird DIC arrangement with epi DIC prisms, I also like to see this kind of stuff

Time ago I tested a related idea: to use a Zeiss Epiplan 16X objective with its dedicated reflected DIC prism as condenser. It worked with a Leitz NPL Fluotar 16X objective but not better than with the DIC condenser, so I abandoned the idea.

viktor j nilsson · Post by **viktor j nilsson** » Sun May 31, 2020 9:39 am

Pau wrote:Hi Viktor,

Would be nice to see you weird DIC arrangement with epi DIC prisms, I also like to see this kind of stuff

Time ago I tested a related idea: to use a Zeiss Epiplan 16X objective with its dedicated reflected DIC prism as condenser. It worked with a Leitz NPL Fluotar 16X objective but not better than with the DIC condenser, so I abandoned the idea.

Oh, you're going to like it, I hear! My latest efforts are going in that direction: to improve my DIC at 40x, I've started using various 40x objectives as condensers. Since this means that the setup is perfectly symmetrical (identical prisms, objectives with same focal length) it should, in theory, produce excellent DIC. The problem right now is that the interference fringe is located a bit too high for the 40x objective.

I definitely plan to share it all on here, but it's still very much a work in progress (just like my fluorescence experiments!).

Edit: I haven't tried it yet, but it would be cool if it was possible to get DIC at 4x with an objective as condenser (and it suddenly makes it more reasonable to have multiple good objectives at each magnification. I knew it would pay off!).

Pau · Post by **Pau** » Sun May 31, 2020 10:36 am

Sure!
I'll wait to see it.

At least with high magnification that symmetry will be broken by the difference between slide and cover slip, maybe making the preparation between two covers...

viktor j nilsson · Post by **viktor j nilsson** » Sun May 31, 2020 10:48 am

Pau wrote:Sure!
I'll wait to see it.

At least with high magnification that symmetry will be broken by the difference between slide and cover slip, maybe making the preparation between two covers...

True! I hadn't thought of that. The dual coverglass approach could be a viable approach in that case.

I haven't really ventured into high NA microscopy myself (my sample prep technique is still rather poor). I actually don't have any high quality 100x objective (only two E plan 100x). My highest NA objective is my Fluor 40x 1.30. It will be tricky to get good DIC at 40x 1.30, unless, of course, if I pick up another one....

René · Post by **René** » Fri Jun 05, 2020 4:45 pm

Hi viktor, I've got one of those. The old PL lenses (with phase rings) are ##### in dic. The newer splanapos don't work with it. Try leitz npl fluotars! I have 10, 25, 40, 40 oil and 100 apo in use..

Best wishes, René