How to attach camera to Olympus BH2?

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microcosmos
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Re: How to attach camera to Olympus BH2?

#31 Post by microcosmos » Tue Aug 31, 2021 5:07 am

Thank you and sorry for not checking Alan Wood before posting.

microcosmos
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Re: How to attach camera to Olympus BH2?

#32 Post by microcosmos » Thu Sep 02, 2021 6:11 am

Scarodactyl wrote:
Mon Aug 30, 2021 4:37 am
The PE is an economical choice--they sometimes comr up very inexpensively. The u spt probably sits higher because the tube lens is in the dovetail of the head, requiring 180mm from that point, while in a BH2 infinity system the lens sits about 20mm lower below the head.
I imagine it would be easy to 3d print a replacement dovetail with a wider hole to bolt on after removing the existing dovetail, much like DennyNY's nice work above. That would also be very easy and relatively inexpensive to iterate.
Here's what I have so far, with minor modifications from the original design. The model was drawn in FreeCAD.

Image Image Image

The hole is now 25 mm to accommodate the 24.8 mm PE.

I made the internal geometry slightly simpler and let the crossbeams and central bore go all the way to the bottom instead of cutting them off halfway up. This makes it stronger and more rigid although this is probably not needed. Any comments on improving the design are welcome.

I'll do some finishing touches and look into fabrication.

microcosmos
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Re: How to attach camera to Olympus BH2?

#33 Post by microcosmos » Sat Sep 04, 2021 1:50 am

Here are the dimensions.

Image

The part has passed manufacturability assessments - this shows one of the results, generated by Proto Labs. It is not possible to remove the material indicated in blue, but they are all non-critical.

Image

microcosmos
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Re: How to attach camera to Olympus BH2?

#34 Post by microcosmos » Sat Sep 11, 2021 6:16 am

CNC machining the modified dovetail in stainless steel:

Image

(Video kindly taken by my local workshop 3D Print Singapore)

microcosmos
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Re: How to attach camera to Olympus BH2?

#35 Post by microcosmos » Wed Sep 22, 2021 11:48 am

Here it is alongside the Olympus original:

Image

It is has a black oxide finish deposited using the quench-polish-quench method, to minimise any scattering of stray light from the trinocular head below, as the light from below isn't being channelled along a narrow tube at that point.

I took the calculated risk to have it machined before I actually got the PE eyepiece, in order to expedite matters, so I based the dimensions on the 24.8 mm of the PE tube given in online documentation. However, when the PE actually arrived the middle section of the tube was like 25.1 mm and too big to fit. So I sanded it down. Now it has a nice "Limited Edition" brushed silver finish:

Image

After that, everything fitted nicely on the microscope but I have had no time to take any pictures yet. At 335g my "military" version weighs three times the original, but it's still light enough. The army does have a habit of making really heavy hardware.

Screenshot 2021-09-22 at 19.44.35.png
Screenshot 2021-09-22 at 19.44.35.png (476.13 KiB) Viewed 15395 times

Scarodactyl
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Re: How to attach camera to Olympus BH2?

#36 Post by Scarodactyl » Wed Sep 22, 2021 3:17 pm

Very cool! I'm looking forward to hearing how it works. Hopefully well, as I imagine it wasn't cheap to have made, but if it works it should easily be worth it.

Dubious
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Re: How to attach camera to Olympus BH2?

#37 Post by Dubious » Wed Sep 22, 2021 5:06 pm

Impressive work.

microcosmos
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Re: How to attach camera to Olympus BH2?

#38 Post by microcosmos » Thu Sep 23, 2021 6:56 am

Thanks everyone for your advice and I'm glad this project is of some interest. Unfortunately I have to bring you bad news - the image quality is no good (although it is parfocal) if you're using a system similar to mine.


First a recap of my system:

- UPLFLN-P objectives (UIS2).

- BH2-MA-2 vertical illuminator. A mysterious variant of the BH2-MA. The MA-2 appears to have two lens elements/groups as the tube lens rather than one, and has a considerably longer tube than the MA, although both are marked as f = 180.

- PE 2.5x photo eyepiece.

- an 18-megapixel full-frame 35mm-format DSLR - I think this is an aggravating factor as the resolution of the sensor is much higher than the resolution of the microscope, so aberrations are more obvious when you zoom in.


And the findings:

With the UPLFLN-P 10x objective, there is serious magenta-green fringing if you zoom in 100% on the image pixels.

With the MSPlan 10x (which I temporary put on the microscope for comparison), there is serious purple-green fringing on 100% zoom-in.

So it seems that as long as there is a combination of BH2 and BX components, it won't work. This is already known so it's not surprising.

With the UPLFLN-P 40x and the MSPlan 50x, the aberrations are much gentler and more orange-green.


I didn't make comparisons with my NFK eyepiece as I felt it was too much trouble to unscrew and disassemble the whole thing just to find that the image quality was no better since there were still BX components in the system.

As explained elsewhere, I had other reasons for introducing UIS objectives into my system and they still give better (and very usable) images overall for my particular applications than using the corresponding BH2-era objectives.

So I have decided to just let it be and continue using the PE eyepiece - enough time spent tampering with the photomicrography setup, enough engineering and design skills learnt, and time to move on to actually using the microscope for the research I want to do. I almost never crop my images and they still look very good uncropped up to moderate display sizes.

In fact, before the dovetail was ready, I was taking photos through the eyepiece using a point and shoot (with a large and good sensor) and they look just as good at normal sizes except for the black rim at the sides and a bit of vignetting and field curvature which actually makes it nicer because it makes it look like you're looking through a microscope.

In any case, if you're interested in the modified dovetail for whatever reason, you can see all the details and download the 3D CAD file here: https://www.linyangchen.com/Olympus-BH2-trinocular-head-dovetail-UIS

Scarodactyl
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Re: How to attach camera to Olympus BH2?

#39 Post by Scarodactyl » Thu Sep 23, 2021 7:17 pm

That's a shame, though maybe still something that can be adjusted around. Uis/uis2 objectives should be reasonably compatible with everything here, and even the potential issues introduced by the tube lens should be limited to far edges and cropped off by the pe eyepiece (though my own experience is only with the bh2-uma).

microcosmos
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Re: How to attach camera to Olympus BH2?

#40 Post by microcosmos » Fri Sep 24, 2021 1:42 am

Glad to hear from your experience that the combination of UIS(2) and BH2 tube lens should actually work ok.

Your suggestion that something could be adjusted made me think of something. The PE eyepiece actually has two snake-eye screws, one on the bottom lens and one in the middle lens that is accessed by unscrewing the upper head of the eyepiece. I wonder if adjusting those snake-eye screws (and therefore altering the relative positions of the three lens groups in the eyepiece) might improve matters. It is possible that those adjustments don't just change parfocality, and even possible that Olympus made them adjustable so as to alter the compensation characteristics for different objectives.

But to do the adjustments without specialized optical apparatus, I will have to dismount the camera, extricate the now very-tightly-fitting eyepiece from the dovetail, unscrew the head, turn the snake-eye in a very dangerous way with a pair of needle-nosed pliers, screw back the head, stuff back the eyepiece in the tube, remount the camera, take pictures, and repeat the whole thing about 10 times. And there are two lenses whose positions can be adjusted, so it's 10 permutations on 10 which is hundreds or thousands of relative lens positions to test. It's simply not possible for me to do it. And maybe after all that I might discover that it doesn't fix the aberrations!

However I'll be grateful for any suggestions. Maybe there's an easier way.

Scarodactyl
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Re: How to attach camera to Olympus BH2?

#41 Post by Scarodactyl » Fri Sep 24, 2021 1:57 am

I am mostly wondering if there is possibly a positioning issue with the eyepiece, or maybe something optically active in the light path adding additional aberrations. Sample photos would help as well to habe an idea.

microcosmos
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Re: How to attach camera to Olympus BH2?

#42 Post by microcosmos » Fri Sep 24, 2021 4:00 am

I know it's ridiculous but I can't actually post sample micrographs right now that show the problem. The microscope is in a separate room from the computer, so to actually get the photos onto the Internet I have to dismount the camera and take it into the other room to connect it, start up the software and download the photos and covert the raw files to jpeg. I'm not feeling like going through this procedure right now, as I don't really think the aberrations can be fixed completely, even if they can be improved.

And I'm actually enjoying taking pictures through the viewing eyepieces with a point-and-shoot - they look more "photojournalistic". At the moment the big camera is a sort of white elephant that makes the microscope look more impressive, except when I need photos that have completely no vignetting and for focus stacking, for example.

I tried taking pictures of the LCD screen on the camera using a smaller camera to post and show the aberrations, but it didn't work as the LCD pixels caused moire that obscured the actual aberrations.

The photo eyepiece seems parfocal and the image is sharp, just aberrated purple/magenta and green - are you referring to the possibility of the eyepiece being tilted? It doesn't seem to be the case as the aberrations are right in the centre of the image as well. I also doubt the eyepiece is tilted as the dovetail mount was CNC machined accurately and the fit is very tight.

I swung the BH2-MA-2 half-mirror out of the light path so it wasn't affecting the image. The rest of the stuff in the photo light path are the tube lens and the prism in the BH2 superwide trinocular head.

Perhaps the tube lens in the MA-2 somehow isn't as "universal" as the one in the UMA. Or perhaps different UIS objectives react differently to BH2 optics since the two were not explicitly designed to go together. Perhaps your objectives are better ones (plan apo?) or just happen to be fine with the BH2 system.

I have to admit there are other things on my mind at the moment - centering the objectives and calibrating the graticule etc. and moving on to analyzing some backlogged petrographic slides. The aberrations are not bad enough to be an issue right now - neither in the analysis nor in the uncropped photomicrographs for web display. I apologize if it seems I'm not putting enough effort into fixing this CA problem. I haven't completely given up on it - I just need to find a more suitable time to investigate it further!

Dubious
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Re: How to attach camera to Olympus BH2?

#43 Post by Dubious » Fri Sep 24, 2021 4:32 am

Is it possible to adjust placement temporarily to form an image without the PE eyepiece? It might be interesting to see what that does to the CA.

microcosmos
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Re: How to attach camera to Olympus BH2?

#44 Post by microcosmos » Fri Sep 24, 2021 4:43 am

Hang on - I forgot to mention the most crucial bit that could explain the problem. The intermediate polarizing attachment! It’s stacked on top of the MA-2. One is not supposed to do that.

On the original BHSP, this attachment has a 1x factor that I assume keeps the finite tube length at 160mm. I’m not sure what it does exactly when I stack it on top of an infinity tube lens - does it maintain the 180mm tube length or does it lengthen it? I’m inclined to think the latter, as there is a bit of vignetting in the superwide eyepieces with high-powered objectives that isn’t there when either the polarizing attachment or the vertical illuminator aren’t installed. In either case the polarizing attachment would probably interfere with aberration corrections in the rest of the system as it’s totally unexpected to be there.

Alas it’s too late to take off the attachment to test the PE. I’ve already oriented the polarizers and aligned them to the stage and crosshairs so if I disassemble it I’ll have to do everything all over again. Perhaps I could do it the next time I overhaul the instrument.

microcosmos
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Re: How to attach camera to Olympus BH2?

#45 Post by microcosmos » Fri Sep 24, 2021 4:52 am

Dubious wrote:
Fri Sep 24, 2021 4:32 am
Is it possible to adjust placement temporarily to form an image without the PE eyepiece? It might be interesting to see what that does to the CA.
Yes I think it is, but I’ll have to disassemble the setup and find a way to attach the camera closer down to the head to have a meaningful image size to compare with.

I just need to find a chance to do this properly further down the road. Photomicrography is not at the top of the priority list at the moment although I do want it as optimized as possible.

microcosmos
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Re: How to attach camera to Olympus BH2?

#46 Post by microcosmos » Fri Sep 24, 2021 4:57 am

And actually I did consider direct projection for photomicrography, but (as has also been noted in another thread) the protruding bottom part of the BH2 chimney prevents me from positioning the camera close enough to the head to fill the frame with the image.

Scarodactyl
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Re: How to attach camera to Olympus BH2?

#47 Post by Scarodactyl » Fri Sep 24, 2021 6:42 am

microcosmos wrote:
Fri Sep 24, 2021 4:43 am
Hang on - I forgot to mention the most crucial bit that could explain the problem. The intermediate polarizing attachment! It’s stacked on top of the MA-2. One is not supposed to do that.
This is probably it, yeah. This would have lenses built in to compensate for the added space which are now only able to cause trouble.

microcosmos
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Re: How to attach camera to Olympus BH2?

#48 Post by microcosmos » Sat Sep 25, 2021 3:01 am

I decided to try using the camera with the PE eyepiece after all. It's bad enough that I need to do something about it.

Here's an uncropped image (18 megapixels, not high by today's DSLR standards but still too high for the microscope's resolution) of a pyroxene in a 30 μm petrographic thin section in plane-polarized light. I chose this mineral to see the worst-case scenario as it has a very different refractive index from the mounting medium and also lots of pits on the surface, which would worsen any aberrations.

Image

I am not happy as the purple-green fringing is visible even when uncropped. Here's a 100% zoom-in:

Screenshot 2021-09-25 at 10.21.49.png
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I was somewhat surprised that the photos I took using the point and shoot camera (a Ricoh GRII, which has a fairly good APS-C sized sensor) through the SWHK eyepieces look much better - sharper and with less colour fringing (another pyroxene shown) (sorry the colour balance is a bit off):

Image

Here's a 100% zoom-in of the point and shoot:

Screenshot 2021-09-25 at 10.56.21.png
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However, part of the difference may be because the PNS covers a significantly larger field of view and has a lower megapixel count than the DSLR.

You can see vignetting in the periphery of the circular 26.5 field of view with the 10x objective. That's caused by stacking the intermediate polarizing attachment on top of the vertical illuminator. It can be alleviated by opening up the aperture diaphragm all the way but the contrast will be affected. The field is still flat all the way to the edges though.

Both photos involved the 10x UPLFLN-P which seems to be the worst compared with the 4x and 40x UPLFLN-P. It seems that the 4x is of low-enough magnification that CAs are easier to avoid (still visible but barely), while the 40x seems to be helped by the swing-in top lens of the BH2-POC condenser, which significantly reduces CA.

When I swing in the condenser top lens with the 10x (and refocus the condenser appropriately), it actually removes most of the CA and improves the image significantly, but the field of view is reduced such that there's a wide black border in the eyepiece view.

Given how bad the PE is doing, I feel compelled to swap the NFK back in and see if that improves matters. I'll update again.

microcosmos
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Re: How to attach camera to Olympus BH2?

#49 Post by microcosmos » Sat Sep 25, 2021 6:31 am

Test results NFK 2.5x vs PE 2.5x projection eyepiece

setup:

- Köhler illumination with plane-polarized light (as the polarizer cannot be swung out of light path)

- UPLFLN-P 10x objective

- BH2-MA-2 vertical illuminator with BH2-PA intermediate polarizing attachment stacked above it

- BH2 superwide trinocular head (some additional optical components in light path)

- Canon EOS-1D X with white balance zeroed manually to the halogen lamp (at full rated voltage with daylight blue filter) using NFK eyepiece. This white balance calibration was also used to take the PE photo, so it reveals any colour difference between the two eyepieces. Image set at neutral with no added contrast/sharpness/saturation. Colour noise reduction set to 1.0 in Canon Digital Photo Professional software, luminance noise reduction set to 0. ISO 100. Mirror lockup. Raw files converted to highest quality jpeg for display below.

- sample: 30-micrometer thick petrographic thin section with coverslip, showing pyroxene with high relief.

In all images, the NFK is on the left and the PE is on the right.

Uncropped:

Image
NFK slightly redder, PE slightly greener colour cast it seems. Could be due to the difference in aberration colours detailed below.

100% crop in the centre:

Image
NFK slightly worse fringing and redder than PE but difference is very small. NFK seems a bit sharper than PE (assuming I focused both identically which may not be the case. I did the manual focusing using camera's live view on its LCD screen zoomed in moderately to have the best judgement based on small detail while still having enough field of view on LCD screen to gauge overall focus.)

100% crop lower left corner:

Image
NFK better aberration correction and better field flatness in the corners. PE has yellow separation as well.

100% crop upper left corner:

Image
NFK better aberration correction and better field flatness in the corners.

Winner (for me): NFK.

So the military-grade black oxide steel dovetail becomes a nice Olympus Limited Edition collectible paperweight.

It will be interesting to know if the field curvature and corner aberrations of the PE happen when it's installed on a proper compatible BX system with full BX UIS optics as well.

Thank you very much for staying with me through this. It took a lot of time but now I know I have the better of the two options for my setup.

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Re: How to attach camera to Olympus BH2?

#50 Post by Scarodactyl » Sat Sep 25, 2021 6:58 am

Weird. Thinking about it the polarizer in theory should be fine for color correction, I was just mixing it up a bit. So this is a real puzzler, something is specially incompatible but darned if I know what.

microcosmos
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Re: How to attach camera to Olympus BH2?

#51 Post by microcosmos » Sat Sep 25, 2021 7:22 am

So it's not just the stacking of the intermediate polarizing attachment on top of the vertical illuminator that's causing this? Did you think there must be something else making it even worse?

Could it somehow be the Abbe condenser? I noticed that when the condenser top lens is flipped in, the aberrations are much reduced.

microcosmos
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Re: How to attach camera to Olympus BH2?

#52 Post by microcosmos » Wed Oct 20, 2021 1:29 pm

Hmm, I just visited this Leica webpage that has numerous micrographs taken with their flagship DM4 P.

Their micrographs in plane-polarized light seem to have even worse green-purple fringing than mine, including the ones taken with the Plan Fluotar objectives which I assume are similar in aberration correction to my fluorite objectives.

It seems that the issue is not solely caused by my particular setup. Can anyone explain this?

AlexPhilip
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Re: How to attach camera to Olympus BH2?

#53 Post by AlexPhilip » Thu Oct 21, 2021 9:41 am

The easiest way is to use a tmount port and adapter. Most old microscope set-ups used film slr to take pictures and standardized the t mount. So if you need a c mount to tmount port adapter and your cameras fitting.

Andreylien
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Re: How to attach camera to Olympus BH2?

#54 Post by Andreylien » Thu Dec 22, 2022 10:08 pm

DennyNY wrote:
Sat Nov 23, 2019 5:36 am
Ok it works,
I make 3D printed version of dovetail with small modification.
I bring NFK lens lower by 5 millimeters and it allow me to adjust focus via U-PMTVC.
If anyone interested in 3d file let me know i will share.
Thank you everyone who try to help me.
Is there any chance I could have the 3D file, please?

Tailgunner
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Re: How to attach camera to Olympus BH2?

#55 Post by Tailgunner » Fri Dec 01, 2023 10:58 am

DennyNY wrote:
Sat Nov 23, 2019 5:36 am
Ok it works,
I make 3D printed version of dovetail with small modification.
I bring NFK lens lower by 5 millimeters and it allow me to adjust focus via U-PMTVC.
If anyone interested in 3d file let me know i will share.
Thank you everyone who try to help me.
Is it possible to send me the file? I tried sending a private message but they seem to get stuk in my outbox.

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