Does it make sense to use Nikon CFN lenses on a olympus BH-2?

[Seta]

Hi,

Last week got my first microscope; well, I got a mitutoyo FS-50 head few years ago but never got to adapt it the way I wanted and sold it. Lets say is my first biological microscope.

A very dusty BH-2 (Edit:BHT) with D Ach lenses and the swing out type condenser. Everything seems to work fine, only the lock lever seems to be stuck, I do not want to force it. Maybe I will disassemble the whole thing and clean it. I also bought the trinocular head for it, have not received it yet.

Although I am new to microscopy I have experience with focus stacking photography and I own several microscope objectives like mitutoyos, Nikon CFI60 lenses, nikon M/BD plans and others.

I want to do photography with it and first problem I can think of is BH-2 needs corrective projection eyepieces. I use an APS-C camera so the ideal one would be the NFK 1.67x which is both rare and expensive, not interested in the NFK 2.5x. The alternative is to use the afocal method, which I have already tried via the WHK10/20 L eyepiece and a Konica Hexanon 40mm 1.8 pancake lens.
I have also tried some of my nikon BD/M plans via direct projection and seems to work well too. I have to say I am getting a mild hot spot (blue spot) with both methods but I guess it is caused by the extra glass on the binocular head, which is not meant for photography.

For me image quality is important so I wanted to upgrade to at least to the Olympus S plan lenses but seeing that the Nikon lenses work well made me think, what about using the Nikon CFN 160/0.17 objectives on the BH2 via direct projection? maybe is better to take this route...I do not really mind if the S Plans are a little better (I do not know if they are, I think CFN lenses would/should be pretty similar) if I can not get the most of them without the NFK 1.67x

I rather not invest in Apo/fluor lenses until I get some experience with the scope but I may also try to add an intermediate tube lens to use some infinity lenses I own too.

Javier

[Hobbyst46]

A BHS for a first microscope is an excellent starting point ! Congratulations !
The Alanwood Olympus site offers detailed maintenance documents, by Carl Hunsinger.
SPlan objectives are excellent, yet indeed color correction (at least) is best achieved with Olympus eyepieces.
From my very humble experience, Nikon CF objectives are excellent too, so worth a try. The risk is lack of exact parfocality with other objectives.

[PeteM]

A few thoughts.

Olympus SPlan objectives and Nikon CFN finite objectives (the larger barreled ones with slightly higher numerical apertures) are essentially equivalent. The Nikon Plan CF objectives are equivalent to Olympus DPlan. And within a smaller image circle, the Olympus D Plan objectives are very good.

It doesn't seem you'll be happy with any of them in photo relay mode (SPlan, DPlan, or Nikon CFN or CF) with your APS-C camera, unless you happen to find the elusive 1.67x projection lens (or maybe the almost-as elusive Nikon 2x) at an affordable price. Not likely.

As for the Nikons having slightly less chromatic aberration when viewed through a neutral eyepiece and a camera lens - to a limited extent yes - but camera lenses can introduce their own issues. It might cost near as much to get CFN objectives as to source a full frame DSLR or mirrorless body -- and use a 2.5 projeciton lens. Just sayin'.

You mentioned having a bunch of Nikon CFI objectives. Another alternative would be to convert your BHS to an infinity scope. There are 25mm turrets available. The BHS has enough room to accommodate your 60mm parfocal Nikon CFI objectives. And you could try direct projection to your APS-C camera.

[Seta]

#Hobbyst46
Yes, I know about Alanwood website; I have been through some of those documents already but I will wait a little before I attempt disassembling the focus block.
#PeteM
I am used to work with finite nikon lenses via direct projection (no eyepiece/no camera lens) with my bellows set up, I used to work with a FF 5D mkII and most of the M/BD plans 210/0 would fill the whole sensor pretty well.
I did own a couple of CFN lenses (the newer type, 4X and 10X) but corner performance on FF sensor was poor; still I am pretty sure those two would work just fine on an APS-C body, I would also expect the same from the other CFNs.
In case some do not I can always use an old 1.5X teleconverter I own and have used in the past. At the end a 1.5X projection lens or 1.5X teleconverter do the same, take the central part of the image circle although do that in a different way.

I would have to use the S Plans like this " S Plan>Eyepiece>Konika 40mm>Camera" whereas I want to use the CFNs like this "CFN>Camera or CFN>1.5x Teleconverter>Camera"; I am kind of surprised there is no more people rtying this set up (maybe there are) because of how difficult is to get that NFK 1.67x or the nikon 2x I did not even know of.

Yes I do own a few CFI lenses LU plan 20/0.50, LU plan 50/0.80 and OEM Plan Apo 20/0.75 VC. Also some CF infinity lenses (45mm parfocal) 20/0.46, 40/0.65 and 50/0.55 ELWD but all these are air lenses, no coverglass. I may sell some of those to fund the CFNs but I will sure try to convert it to infinity, just need and intermediate piece with a tube lens (I think U-TLU has same size dovetail), or I can adapt the Raynox lenses I normally use (just need to figure it how).

[viktor j nilsson]

I can see a couple of issues.

1) will you be able to position the sensor at the correct distance for direct projection using the BH-2 trinocular head? It will depend on how easy it is to remove the chimney. I don't remember seeing it being done, but it could just be that since most olympus users use olympus objectives, they rarely want to.

2) IF you eventually decide to switch from direct projection to using CF PL photo eyepieces, it is not certain that you can do this with the BH-2 head. At least on my Vanox AH, the trinocular port is too narrow for a CF PL 2.5x to fit. The short barrel FK projection eyepieces are significantly narrower than the CF PL. I'm not sure if the NFK eyepieces for the BH-2 are wider. Worth checking out.

3) have you considered using a FF camera instead? 2.5x + FF is a very nice combination.

If you do decide to go down the Nikon route, I can highly recommend the Fluor and Plan Fluor objectives. The CFNs are okay, but I feel that the Fluors are a big step up. The PlanApos (both CF and CFN series) are great if you can find them, of course. But the Fluors can sometimes be found for very good prices, and are really really close in performance.

Your idea of using a teleconverter is a good one. If it is physically possible, that should give great performance. I agree that it is an option that deserves to be considered more often.

[Seta]

Hi Viktor,
Thanks for the extra thoughts,
1) I still do not have the trinocular head, will receive it next week.
I will see if I can make it parfocal but I am used to change the magnification of microscope lenses via extension with bellows, so as long as it works it does not bother me much. But it seems doable

2) I have no intention of using a projection eyepiece, at least for know. But I will try afocal method though with olympus lenses

3) I like working with aps-c these days, I can use lenses that cover FF at smaller magnifications. Eg mitutoyo 20/0.42 at @12.5x and nikon cf 50/0.55 at 31x via 125mm tube lens ( raynox DCR-250)
at the end that gives me same framing I was used to get with FF at a fraction of the cost and with less problems with dust trails/difraction

I could start with the CFN lenses and slowly upgrade to fluor/apo lenses. Do you know of any CF ( those before CFN lenses)brochure/catalogue?

The other option I am considering is adapting cfi60 lenses, can some point me to the right bh2 compatible nosepiece like PeteM suggested? I will first test
them placing the bellows on top, where the trinocular head goes. I would just need a 10 and 40 biological objectives.

Is easy to adapt teleconverters, I have tried a 1.5x nikon mount one and and old m42 one, both with good results

[deBult]

Olympus BH2 objectives require color aberration compensation via the eyepiece.

[Seta]

That I know, that is why I am considering using olympus lenses via afocal method ( with WHK 10/20L eyepiece) vs nikon CFN lenses via direct projection.

Another " crazy" option would be to use the nfk 2.5x with a metabones 0.71x speedbooster to turn it into a nfk 1.77x. I have been considering getting one for the Canon MP-E. There is also a speed booster 0.64x XL wich would turn the nfk 2.5k into a nfk 1.6x

Could be an option if I already owned good quality ( APO) olympus lenses

[c-krebs]

You're asking all the right questions. And you have already gotten some good into. I'll try to add a little more to the mix.

You didn't mention what camera you are using other than it is an APS-C format. If it is a DSLR it will be extremely difficult to do "direct projection" (if even possible) with an Olympus trinocular head because of the body depth. With a mirror-less camera that has a flange focal distance of around 18mm it might be possible. You don't mention which Olympus trinocular head you have coming... likely either the BH2-TR30 or the BH-TR30. The pictures below are those two heads.





If you look at the top of the BH2 head you see a smaller dovetail mount. As mentioned in previous replies, the mount is only wide enough to properly fit an Olympus NFK photoeyepiece. A regular eyepiece will not seat all the way down as the eyepiece top is too wide. So that makes it not suitable for an "afocal" setup or direct projection. I don't know how much DIY you are comfortable with, but the top part of the BH2-TR30 is easily removed with three machine screws at the top. As indicated, this lowers the trinoc tube about 36.7mm. If you are handy, you could then add an extension that could accommodate a "regular viewing eyepiece" at the proper location to do "afocal", or fit a Nikon projection eyepiece. Even better, it may allow you to do direct projection. Now I don't know where the intermediate image resides in that tube... it will be somewhere in the space where the top section was removed. If (a big if!) a mirrorless body could be positioned so that the intermediate image fell on the camera sensor you could do direct projection.If the distances "work" it should be pretty easy to do. (I've never tried it because I use Olympus objectives with the NFK photoeyepieces).

The older BH-TR30 can position a regular eyepiece to do "afocal". But I don't know if that chrome top section is easily removed to try direct projection with a mirorless body.

As to objectives it is a decision you need to make. If "direct projection" is your ultimate goal, then it would clearly be best to avoid optical systems that are designed to use final correction in the eyepieces. Both the Olympus S-Plan and Nikon CFN are very good. And with a little patience you should be able to get nice samples of these or even Plan Apos for a reasonable price. The BHS is a very nice scope. The 100W light source is great, and there is a good supply of accessories still available.

You had asked about a Nikon CF brochure. See if this helps:
https://krebsmicro.com/Nikon_CF.pdf

There is another approach you didn't bring up. It's possible to not use a microscope viewing head at all and just mount the camera at the appropriate location for direct projection. If the camera you are using has a nice articulating screen you could use that or connect an external monitor (or computer) to the camera. This could be done with just about any camera, even DSLRs.

Whatever camera you use, I very stronlgy recommend using an electronic shutter (or a shutter that has an electronic first shutter curtain... and even some of those are not "perfect"). Otherwise the vibration created by a microscope mounted camera can seriously degrade image quality.

[Seta]

Hi Charles, thank you for giving me your insight, really appreciate it.

Yes, I forgot to mention; I own two sony bodies ( NEX-5N and A5100) connected to a 23" 1080p tv; the trinocular head is the first one BH2-TR30. It comes with an extra pair of WHK 10/20 L eyepieces and a projection eyepiece. MCA LB NEOPLAN TV LENS, which I have not found any info about; I have just seen the nfk1.67x was recommended projection lens for tv so I wonder how this one will work.

I saw in one of alan's site documents trinocular head has three screws that can be removed as you say. I am ok with DIY, have lots of different extension tubes and step up/down rings, also a telescopic m42 tube( around 9-15cm length maybe) and a NEX-M42 focusing helicoid, that should help with parfocality.

My scope came with the 20w lamp (Sorry, I said BHS and it is a BHT)but I am using a 6w ( can be driven to 12w max)5000k cri 97 bridgelux cob led in its place, I want to make it dimable so I will have to change few things like getting buckpuck drivers. Would be cool if I could use the original bh2 light attenuating fader

I plan to use BF, DF, Cross polarized and rheinberg filters. All these seem easy to get at low cost...no plan for DIC or other more advanced techniques in the near future, as I said I am completely new to scopes. Good thing is this is a system that can keep growing if I want too.

Unless olympus lenses performance with MCA projection lens is really good I will probably take the nikon route, I have the feeling less glass on the set up reduces the chances for image quality loss . Besides I could use those nikon lenses in my more traditional bellows based vertical set up too althogh I am well covered

I do not know if you still use the bh2 finite setup, I think to recall most of your work is done with infinite objectives these days.
Javier Replinger ( jotafoto) and I bought U-TLU tube lenses years ago but moved the glass to custom m42 tube ( they were cheap). I will try to put it back to its original form, but Javier has to send me the housing first; unless I am wrong dovetail size is same as BHS. I never got to use the U-TLU because corner performance was poor but maybe those tests where run on a FF camera, I do not remember. Also own 3 raynox tube lenses, I could try to use the 5.9 diopter one instead if can fit inside U-TLU

That would allow me using the cfi60 and other nikon infinite lenses I own; this would be a not-so-far-in the future goal, I would still need to get some 0.17 lenses ( maybe a 10x and a 40x to start with, the only cfi60 0.17 lens I own is a 20/0.50 fluor one. For this to work well I would also need 25mm nosepiece but can try them first with 25mm/rms adapters. As I said no hurries, I can start with a finite system to give me time to plan the infinity transition well. I do not mind buying cfn lenses now and selling them later on if the infinity project finally works well; I do that all the time. Is is a pity I can not use the mitus on the BH2 but for that I have the bellows vertical set up.

Adding a stepper motor is a higher priority, I do not fancy going back to manual stacking.

That is the cfn nikon brochure, right? I was talking about the previous cf generation. I have seen few reasonably priced cf fluor/apo lenses but I do not know how they compare to the newer cfn ones.

Why not get a nikon scope to start with then? Not so many second hand scopes here in Spain and international shipping for heavy products plus customs if from outside EU add up( few hundreds). When I found the bh2 locally for 145€ I went for it. Paid another 200€ for trinocular head with extras shipping included, if I take the direct projection route I will sell the binocular head with eyepieces, the MCA projection lens and D ach objectives

I am away until next Wednesday, I will load some pictures when I come back home

EDIT: I also have to look at olympus infinite lenses catalogue (Uplanfl, UplanflN) They are rms with 45 parfocal, should not be a problem to sell my cfi60 lenses and get some of this instead..may be makes more sense

[Seta]

Some updates;
Yesterday I received the BH2-TR30 trinocular head. I went ahead and modified it to use it with nikon finite lenses, everything I used I already owned. May need to get some new adapters to finetune it. I like how compact the set up is compared to some phototube set ups I have seen



- I could not manage to form any image with the provided MCA LB Neoplan TV Lens, no matter how close or far away camera was.. I even tried afocal method to see if it was ment to be used that way, no luck either; any clue in how to use it?. Glass is on the narrow part of it, the top part unscrews and has no glass. Some pictures of it


- So next I went ahead and unscrewed the top part of the trinocular tube (closed the trinocular head with the lever in case I droped something accidentaly) , then I took a 37mm to 58mm step down ring and with help of the spacer ring trinocular head has drilled 3 holes on it. So now the trinocular head has a 58mm thread. Then I used a 58mm circular polarizer with no glass that allows me to rotate the camera, 58-52 step up ring, 52-52 female-female ring and a Nex-52 male adapter. EDIT: Focus is of by 20-40 um but tube length is off by 20mm, waiting for right adapter to fix it. I have a 13-20mm nex-m42 focusing helicoid I plan to use but need new step rings I do not have, for now I rather be able to rotate the camera than be perfectly parfocal.
To make it parfocal I plan getting a 37 male-58 female step up ring, a thin 58mm polarizer (without glass, to rotate the camera), M42 male to 58 male, NEX-M42 Focusing Helicoid. Need to measure everything to be sure.





- I also added a 52mm linear polarizer on top of microscope light via a couple step down rings (52-58, 58-67), which fits nicely. A polarizer film from 3D cinema glasses sits between trinocular head and nosepiece. With the help of some step ring I also made a condenser filter holder for 32mm filters, for now it is just taped to it, but does work (not pictured).



- I removed the lamp and added a 6W (can be driven to 12W) 5000K CRI97 COB LED, holding it with an articulated arm for now.


- So far I have tried nikon finite BD/M plans and although they are designed for 210mm tube they do work very nicely with good corner performance. I can also use a 1.5x Vivitar teleconverter (NEx-nikon adapter>Vivitar TC>nikon M42>M42-52 male adapter) for lenses that do not cover APS-C well. It does work, however depending on the subject I can get a mild hot spot, this is a common problem with lenses that were design for film when used on digital cameras. I also own and old 2X M42 TC



- I think I will take the nikon CFN route, get the CFN plans first and with time replace them with Fluor/APO versions. Between those and the BD/M plans I already own I think I will be well served. I could try to adapt the WHK10/20 L and used afocal method, it just seems not worthy. If I owned lots of olympus APO glass I would look for a NFK 1.67x but is not the case.

- No hurries for going to infinity, but I finally decide to take this route I think I will stick with 45mm parfocal. I do own a few nikon nikon infinity lenses I use with my vertical set up; 4x and 10X BE plans(these owning the Mitus I do not use at all) plus a couple (20x and 40x) of nikon CF BD EPI lenses and the CF 50/0.55ELWD RMS. Maybe a 20, 40 and 60/100 Olympus biological 0.17 infinity lenses would be enough to cover this route. For that the Nikon CFI60 lenses I own would have to go but I do not see myself getting a Eclipse scope anytime soon.

At this time I am just setting everything up, once I make few stacks and have it properly running I may start a new thread with the whole process. Nest I want to add a stepper motor to the focus block and make LED light dimmable.

[viktor j nilsson]

Very nicely done! Good to know that it's possible to do direct projection with the BH-2 trino head. I can't see any reason not to continue with the Nikon CF optics at this point. That is going to be a pretty ideal setup.

[Seta]

Thanks Viktor, I am quite happy with it. With direct projection field of view on the camera is a bit wider on the sides and a bit narrower from top to bottom, comparing it to the WHK 10/20 L eyepieces.

This is a 15X on sensor quick partial stack (35 images with +/- 2um steps ) of a fresh garlic peel, camera is NEX-5N; came out a bit noisy as it was underexposed almos 2EV, my bad. Also I was holding the fine focus knob during the stack, which may have caused some vibrations.

Lens used is Nikon BD plan 20/0.40 210/0, lens is designed for a 210mm tube, with the 160mm BH-2 set up it runs a 15X; I wanted to check corner performance, which is a bit poor at 15x ( quite as expected) but still OK, With these 210/0 lenses I could just use the 1.5 Teleconverter, performance should improve quite a bit. There are some mild CA´s, which are expected for a non APO lens.



And here is the Full size image

[Scarodactyl]

It would also be very easy to get or have made a spacer to add that. Either get an olympus spacer and remove the compensating lenses or just have one 3d printed. You could probably even get one by another brand, there are lots with 42mm dovetails. Easy to add or remove as demanded by the objective.
This really looks like a neat setup. I'd recommend trying a pair of Chinese 23.2mm 10x/22 eyepieces as mentioned a few places around. They play very well with Nikon lenses and give you about as wide a field of view as physically possible. The whks on nikons are something of a mismatch after all.

[Seta]

I guess you mean the spacer for the tube lens, that would be cool but have not seem any one yet and I do not have access to 3D printer either. No hurries anyway.

Thank for mentioning the chinese eyepieces, I read those posts but I am not sure which one is the right one, many different ones to choose from. In fact those 2mm fov would better match what the camera sees. For now the WHKs do the job, to tell the truth I do not notice any extra CAs but I guess our eyes are less sensitive to this optical distortions.

I ended up with 4 WHKs, can sell the together with the binocular head.

[Scarodactyl]

I mean a spacer to get the extra reference distance for finite 210mm lenses. The reason they are 210 on Nikon bd plans is because of the space added by the coaxial illuminator that they assume you will use with them, but you can get an empty spacer too.
There are a lot to choose from but only one model has thr combination of a 23.2mm outer diameter and 22mm field number. It's easy to spot thanks to its very fat top on a very skinny base.

[Seta]

Sorry, I added so much stuff in this post that is starting to be difficult to follow, even for me..

I do not know how to find such spacer, but is the best solution possible..if there was room for a tube lens would be just perfect.
If you could point me in the right direction I would be grateful..I do not know if is allowed to post links but if not you can just send me PM
For now I am just using 50mm extension on the phototube, that gives me the 210mm needed but parfocality with eyepieces is completely lost; anyway, once I switch the camera on I watch the tv monitor rather than through the binocular head.

I guess it will take me a month or so to get the parts I need to have it the way I want (motorized focus block, CFN lenses, dimmable LED light, etc) but so far so good.

Thanks all for the advice given

[Scarodactyl]

Spacers are easier to find for infinity microscopes since they just have to be an empty tube. They did make them to fit the BH2 frame but they cost more because there was a lens in them to compensate for the added distance, a lens you would then have to remove https://www.ebay.com/itm/143701143746
It would definitely be a good place to insert a tube lens, though maybe simpler to swap heads entirely.

[Seta]

Ok thank you; you mentioned other brands that use 42mm Dovetail ..Such as? An empty 50mm tube would be just perfect for using the Metalurgical nikon or fit a tube lens inside. If I search for spacers nothing comes, if I look for intermediate tube those design for polarization and such come up.

I just run another quick test, this time Calcium oxalate crystals cross polarized at 20X, direct projection with Nikon BD Plan 20/0.40.. 30 pictures with 2um steps, 5000K Led light.


In the Full size image there are lots of small details to see, corner performance is better with the extra 50mm extension, obvious.

Same subject with different polarization, I tried to remove some top layer from the stack but that leaves out of focus shadows/CAs


Full size