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

viktor j nilsson · Post by **viktor j nilsson** » Sat Jun 13, 2020 2:06 am

Driving home with the mighty Vanox now. What. A. Monster. Might need to look for a new table now.

The NIC condenser was pristine based on quick inspection. Rotated very smoothly and all prisms looked clear. Focus mechanism was as expected stiff from dry grease, it hasn't been used for 14 years. Didn't want to move it too much, but movement was smooth so I think a clean and recrease will be all that it needs. Nosepiece was stuck so I couldn't check the top prism. Light worked! Stage rotated quite well. That was pretty much what I could have hoped for, so I gladly paid and took it home. To be contributed...

René · Post by **René** » Sun Jun 14, 2020 3:03 pm

viktor j nilsson wrote: What. A. Monster. M

LOL. They do indeed compete with english microscopes from the time for that 'industrial' look. Agreed, Olympus was king in the illumination system.

Anyway, here's my system:

Now, I don't have a good camera at home (being spoiled at work), so I'll have to do with iPhone imaging. At least it shows the whole of a Oly WHK 10/20 eyepiece. Normal work setting for DIC. Generally every lens >10x and <100x was used with the condenser prism 40x. Condenser height was finetuned by setting bias to maximum extinction, and adjusting height to (again) maximum extinction. Field iris is then generally left open a bit more, to maximize aperture.

Leitz Pl Fl 10/0.30

Leitz Pl Apo 25/0.65

Leitz Pl Apo oil 40/1.00

Leitz Apo 100/1.40

Next post with some other lenses.

René · Post by **René** » Sun Jun 14, 2020 3:21 pm

I've put some more lenses on the test for this system:

Leitz achro 25/0.50 (45mm, TL170)

Leitz NPl Fluotar 25/0.75 oil immersion (45mm, TL160*)

LOMO Apo 20/0.65 (33mm)

LOMO achro 40/0.75 water immersion (33mm)

Leitz Fl 40/0.85 (37mm, TL170)

Leitz Apo 40/0.95 (37mm, TL170)

more to follow...

René · Post by **René** » Sun Jun 14, 2020 3:37 pm

And another set with somewhat exotic lenses:

W&H Seibert '4' 30x, NA around 0.6

Leitz 25/0.60 salt water immersion (45mm, TL170)

LOMO achro 30/0.90 water immersion (33mm)

Leitz '7a' 50/1.00 water immersion (37mm, TL170)

And some 60x lenses, not on the image,

Leitz 3mm/1.32 oil immersion (37mm, TL 170)

Zeiss Jena 60/1.00 mI oil immersion (33mm)

Zeiss West Neofluar 63/1.25 oil immersion (45mm), condenser prism 40

Zeiss West Neofluar 63/1.25 oil immersion (45mm), condenser prism 100

viktor j nilsson · Post by **viktor j nilsson** » Sun Jun 14, 2020 4:08 pm

Wow, René! Thank you for taking the time to share all of this. I'm only looking at your photos through my cracked phone screen right now, but it looks like you are generally getting nice, even backgrounds despite the mismatch in magnification, tube length and parfocal distance. The system does looks remarkably tolerant. Those images where you used both the 40x and 100x prisms with the Zeiss 63x objective are especially interesting. What range of background colors are you getting?

Today, I've sorted through all the accessories that came with the Vanox, and disassembled and checked all the major components. Almost everything looks essentially unused and complete. Even the two spare fuses that are listed in the manual are still there. I've also realized that it's equipped with the optional 100W halogen illuminator, which I'm very happy about.

Another thing I've done out of cheer curiosity is to check the 1978 price list on Alan Wood's home page to see what a similarly equipped Vanox AH would have cost in 1978. It came out to a whopping 7000 GBP, which, in today's currency, is equivalent to £35,000 ($43,000) according to inflationtool.com! Of course there are many things that cost a lot of money in 1978 that are worthless today. But it's still a bit thrilling to think about.

René · Post by **René** » Sun Jun 14, 2020 4:22 pm

So I guess it's fair to say this DIC system is quite forgiving in the use of other brand lenses, which is a good thing if you want to settle with a serie that combines well in planicity and chromatic abberation.

Some of the lenses I found that didn't work were Wild fluotars 10/0.45 and 20/0.6 (shame, I love that series), and the newer Olympus splanapo series (20/0.7 and 60/1.4). But for sure, compared to the older Zeiss DIC, it is a lot easier to find working combo's with this Olympus set.

Looking forward to your results, best wishes,
René

René · Post by **René** » Sun Jun 14, 2020 4:40 pm

viktor j nilsson wrote: It came out to a whopping 7000 GBP, which, in today's currency, is equivalent to £35,000 ($43,000) according to inflationtool.com! Of course there are many things that cost a lot of money in 1978 that are worthless today. But it's still a bit thrilling to think about.

Ah yes, lab stuff is expensive. I found it relativising to compare it with cars (man's greatest and most expensive hobby ;-).

What do you mean with the background colour range?
The Olympus polarizers shift the colour towards the blue cool range, which is a good thing when used with warm halogen sources. Therefore, for my LED source I choose a warmer type (4300K or so) than I would have choosen for brightfield.

Best wishes, René

viktor j nilsson · Post by **viktor j nilsson** » Sun Jun 14, 2020 5:02 pm

I meant how the background changes when you translate the prism, if you can get a full range from dark grey to strong blue/green/red with most of these combinations? Well, now I'm just being lazy. I shall soon be able to test it myself.

viktor j nilsson · Post by **viktor j nilsson** » Sun Jun 14, 2020 5:30 pm

One thing I've noticed is that the BH objective prism is located quite far from the objective. I wonder if this could, at least in part, explain the greater tolerance compared to some other systems.

To get an interference fringe that is located so far from the prism, the convergence angle of the objective prism needs to be very small. I wonder if this has the effect of extending the area over which the interference fringe remains acceptably in focus, so to speak, compared to a Nomarski prism with a larger convergence angle and short distance from prism to fringe. Having a prism that is located further from the objective could then possibly make it less critial to precisely match the location of the interference fringe to the back focal plane of each objective. This would help explain - in my mind - how this system can use a single prism for objectives that likely have their rear focal planes in quite different positions.

My prediction would then be that the Zeiss system with a single objective prism that is located further from the objective would be more forgiving than the Zeiss system with objective-specific prisms. But the latter could probably deliver superior DIC when properly matched. I wonder if this is consistent with other people's experience?

René · Post by **René** » Sun Jun 14, 2020 5:32 pm

viktor j nilsson wrote:I meant how the background changes when you translate the prism, if you can get a full range from dark grey to strong blue/green/red with most of these combinations? Well, now I'm just being lazy. I shall soon be able to test it myself.

Ah, oh yes, no problem. Very exciting for the first time, but I never found a use for it. At some stage in DIC-career, you don't use it anymore ;-)

viktor j nilsson · Post by **viktor j nilsson** » Sun Jun 14, 2020 5:35 pm

Ah yes. I'm very much a novice who find it exciting to see all the fancy colors, but I agree that the best images come from the mid-grey to bluish-grey part of the spectrum.

René · Post by **René** » Sun Jun 14, 2020 5:50 pm

viktor j nilsson wrote: My prediction would then be that the Zeiss system with a single objective prism that is located further from the objective would be more forgiving than the Zeiss system with objective-specific prisms. But the latter could probably deliver superior DIC when properly matched. I wonder if this is consistent with other people's experience?

I'm not really sure about this. In any case, I had an old Zeiss DIC system like this Olympus system, and the distance from objective to slider was similar.
Terrible system. Below 16x objectives the condenser top lens 1.4 had to be screwed off for the 0.63 one. Very fiddly. And I couldn't find a single objective below 40 that yielded a uniform background.

Apropos, the newest Oly systems work the same way. But instead of the one slider you can now choose between 3, from low to high contrast and resolution.

I'm off to bed now, good luck.
René

Ichthyophthirius · Post by **Ichthyophthirius** » Mon Jun 15, 2020 11:14 am

René wrote:I had an old Zeiss DIC system

Terrible system. Below 16x objectives the condenser top lens 1.4 had to be screwed off for the 0.63 one. Very fiddly. And I couldn't find a single objective below 40 that yielded a uniform background.

It was the first DIC system, so I think it's understandable that it wasn't all-singing, all-dancing yet.

An occasional problem with that system is matching the slider to the intermediate tube (they had different lengths and therefore distances between slider and objective) and condenser.

There were several generations of that system that are not discernable from the labels. That wasn't a problem originally as they were shipped together but is an issue now with sellers selling the pieces individually.

Did you not get a late generation (1980s new logo) Plan 16 or Neofluar 16 to work?

Regards, Ichty

René · Post by **René** » Mon Jun 15, 2020 12:51 pm

Nah, I was too fed up with exchanging the condensor top the whole time, and that in the lower, most used range. Sold it. But I know many people very happy with the older Zeiss DIC. A dutch microphotographer told me he loves it for its subtle effect.
Kept the Zeiss Standard stand by the way. I think it is one of the nicest designs around. Compared to the Standard, the Oly BH is more a marriage of conveniance

Best wishes,
René

viktor j nilsson · Post by **viktor j nilsson** » Thu Jun 18, 2020 2:39 pm

Tonight I finally had time to start working on the Vanox. I managed to fix the two most urgent issues: I got the condenser dovetail moving and I cleaned and relubricated the spring-loaded screws in the nosepiece and DIC intermediate tube. The power supply is a bit noisy, but the bulb lit up fine with a new 100w halogen bulb.

The first thing I did was to crash into my Klaus Kemp 8 form test slide.

I am not used to having both coarse and fine focus moving the stage, so I instinctively turned the wrong way with the coarse focus wheel (the fine focus wheel still can't be used).

At that point it was already getting late, but I had to at least try the DIC setup with some of my Nikon CF objectives. I don't think I even need to say that these are extremely quick and dirty shots. I used a CF PL 2.5x eyepiece and Canon 5D mark II on an improvised extention tube that was way too short. ISO 800, just straight out of the camera (croppped to just within the field of view).

I tried three objectives:
Nikon CF Fluor 10x 0.50 (10x prism)

Nikon CFN Plan Apo 20x 0.75 (40x prism, 10x didn't work at all)

Nikon CF Fluor 40x 0.85 (40x prism)

My initial impression was "not a disaster, but kind of underwhelming". I could get real DIC at least, the rear aperture was reasonably evenly colored with the 10x and 40x. The 20x was quite a bit off. Racking down the condenser didn't help very much. I got the feeling that adjusting the objective prism didn't really give the effect I expected, and I kept wanting to move the prism further than it could. I never got gray backgrounds, it went straight from blue in the innermost position to some sort of pale orange.

Right now, I think that my DIY setup produce decidedly nicer DIC, with clean gray backgrounds (will need to make direct comparisons, though). However, there are quite a lot of issues with the Vanox that I need to deal with before I can really make a judgement, so I should probably just leave it at that right now.