AO Triocular vs Beam Splitter

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Zuul
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AO Triocular vs Beam Splitter

#1 Post by Zuul » Mon May 11, 2020 8:59 pm

I’m enjoying my new-to-me AO 10, and starting to get more interested in using it for photography. It came with the binocular head. My original plan was to use my iPhone or Nikon J4 (1” Sensor) through the eyeport. I made an adapter for the J4 and have played with it briefly. Because it’s not a parafocal solution, the lack of focus peaking is a problem. I’m also not thrilled with the poor manual controls. The nail in the coffin is that it won’t take video with no lens attached.

So, now I’m looking to up the ante with one of my other camera bodies. I have Micro-4/3 (GX1) which would have many of the same problems. Then there are my DSLRs; a D750 and D500. I’m not particularly keen to hang those full-size bodies off the head.

So now I’m looking for the best, innexpensive solution. The CORVID situation has not left my household unscathed, so budget needs to be minimized as much as possible. The triocular heads I can find at the moment cost about double what I paid for the microscope. Admittedly, I got a good deal on the ‘scope, but that still feels wrong to my frugal half. The other option is to get a beam splitter as used for the 2-head teaching set-ups. I’m capable of doing a fair amount of fab for the mount. I have a small lathe and access to a simple mill. Which solution is going to be the best long-term investment for a shoestring set-up?

Finally, I found this on flea bay, and am wondering how likely it is to be completely unusable. Are the optics very susceptible to damage? Would a good cleaning likely be all that it needs?

https://www.ebay.com/itm/AO-American-O ... Sw5eRdM7MT
Last edited by Zuul on Mon May 11, 2020 9:44 pm, edited 2 times in total.

Hobbyst46
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Re: Triocular vs Beam Splitter

#2 Post by Hobbyst46 » Mon May 11, 2020 9:32 pm

Is your microscope an AO 10 ? the title says IO10...
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Zuul
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Re: Triocular vs Beam Splitter

#3 Post by Zuul » Mon May 11, 2020 9:44 pm

Hobbyst46 wrote:
Mon May 11, 2020 9:32 pm
Is your microscope an AO 10 ? the title says IO10...
Corrected. Thanks!

apochronaut
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Re: AO Triocular vs Beam Splitter

#4 Post by apochronaut » Mon May 11, 2020 10:14 pm

There are coatings on the prisms and they can always be damaged but of the 5 or so of similar ones I have had in my possession, all have been good.......However; the listing you have supplied says it has chips and de-lamination on one of the prisms, so I'd look towards one that is intact.
You can use one of those but they intercept the beam in advance of the telan lens, which has quite a degree of input into the correction of the final image. In order to make one of those work well you need either a monocular head as well or the dedicated monocular photo tube. You can then use the monocular head's ocular tube as the photo tube but it will be at about a 30 degree angle.
The dedicated monocular photo tubes are uncommon but are a sturdy straight up photo tube designed to replace the head. They also have the telan lens in them. They usually sell for about 45.00.

Zuul
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Re: AO Triocular vs Beam Splitter

#5 Post by Zuul » Mon May 11, 2020 10:38 pm

apochronaut wrote:
Mon May 11, 2020 10:14 pm
You can use one of those but they intercept the beam in advance of the telan lens, which has quite a degree of input into the correction of the final image.
In that case, I should probably hold out for a proper triocular head. There isn't much point in going to the trouble of a splitter to then mount another head.

What inspired me was this post. It looked like the camera was directly mounted onto a teaching splitter, and einman reported getting excellent images. Does this style include the telan lens?
einman wrote:
Sat Nov 28, 2015 12:21 am
Option #2 involves using an AO teaching beam splitter between the head and body. This allows for the addition of another head or with an adapter, the Canon EOS T3I as shown below:

Image

apochronaut
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Re: AO Triocular vs Beam Splitter

#6 Post by apochronaut » Mon May 11, 2020 11:09 pm

The image circle doesn't cover an APS-C sensor. It might be o.k. with much smaller sensors. However, there is an undefined ( fuzzy) field stop with a kind of hazy border, coma and lateral ca . I don't remember exactly but I think there is curvature of field and loss of some planarity too. If you are o.k. with cropping to only the acceptable parts of the image surrounding the axis, the system could be o.k. The telan lens does a lot of work in those systems.
oh, yes and the other thing I remember is that the condenser needs to be adjusted way off of what would be it's normal setting , otherwise the background is uneven and parfocality with the the eyepieces is poor. I haven't tried it with any extension of the camera position but it is an infinity image at that point, so it is unlikely to make much difference.

All of those possible camera set ups for the AO system are there; it's just that the telan lens is an integral part of the highly corrected nature of the image.

Zuul
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Re: AO Triocular vs Beam Splitter

#7 Post by Zuul » Mon May 11, 2020 11:26 pm

apochronaut wrote:
Mon May 11, 2020 11:09 pm
All of those possible camera set ups for the AO system are there; it's just that the telan lens is an integral part of the highly corrected nature of the image.
Thanks for your reply. I am genuinely grateful to have your AO expertise here on the forum!

Zuul
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Re: AO Triocular vs Beam Splitter

#8 Post by Zuul » Tue May 12, 2020 1:45 am

Just curious, but would a 110/120 Trino head be an upgrade on my series 10? With the right eyepieces it would give a wider field of view, right?

apochronaut
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Re: AO Triocular vs Beam Splitter

#9 Post by apochronaut » Tue May 12, 2020 11:53 am

Yes, it would be but they have a history. The beam splitting prism is prone to hazing after a period of use, which causes one side to have lower contrast and a little off colour compared to the other. Sometimes it isn't bad enough to be bothersome when the left and right images are blended but sometimes it is . Occasionally you see delamination from the outside in of the circular form of the prism, so a central spot, with a hazed exterior. You will need #181 eyepieces.

Look for one that is listed as "working as it should" or lacking any cautions such as " for parts or repair" or other evasive understatements, that way you can return it at their expense if you have to.

DrPhoxinus
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Re: AO Triocular vs Beam Splitter

#10 Post by DrPhoxinus » Tue May 12, 2020 12:18 pm

I searched eBay for American optical trinocular and the first. hit was a 1043 head for 60 or best offer and then a 110 scope for a 100

I think I have an extra aluminum tube for the trinoc somewhere

Gerard

Zuul
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Re: AO Triocular vs Beam Splitter

#11 Post by Zuul » Tue May 12, 2020 6:11 pm

DrPhoxinus wrote:
Tue May 12, 2020 12:18 pm
I searched eBay for American optical trinocular and the first. hit was a 1043 head for 60 or best offer and then a 110 scope for a 100
I saw those, but the condition based on their pictures didn't give me a lot of confidence. There are others, too, for not too much more. I'm still weighing options...

Can somebody identify this head? I've only seen Trino's for the AO 10/20 with the switch on the back. Is this for earlier models? (i.e. not infinity objectives)

Image

apochronaut
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Re: AO Triocular vs Beam Splitter

#12 Post by apochronaut » Tue May 12, 2020 6:14 pm

That's a series 4. There is no telan lens. Some use them for astro binoculars.

Zuul
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Re: AO Triocular vs Beam Splitter

#13 Post by Zuul » Sun May 17, 2020 7:24 pm

Well, I haven’t picked up a head yet, but I did snag a #437 to use as a projection eyepiece. It seems like that is the safest path for high quality images.

On a loosely related note, I was wondering about tube lens compatibility. If a 410 Trinocular head popped up, how far off is the correction when used with the older 34mm objectives? This is mostly idle curiosity, mind you.

Speaking of objectives, I spotted and obtained a mixed lot that included a 20x. Now I have a complete Plan Achro set. (1017, 1019, 1022, 1023, 1024) I’ll keep an eye out for a fairly priced quint turret. Will any AO nosepiece fit? 10,110,410? All generations use the same 2” dove tale, right?

geo_man
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Re: AO Triocular vs Beam Splitter

#14 Post by geo_man » Tue May 19, 2020 11:38 pm

Hi all, I was also interested in Zuul's question: "On a loosely related note, I was wondering about tube lens compatibility. If a 410 Trinocular head popped up, how far off is the correction when used with the older 34mm objectives?"

Anybody know? Thanks.

apochronaut
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Re: AO Triocular vs Beam Splitter

#15 Post by apochronaut » Wed May 20, 2020 12:11 am

It depends on which objectives , which eyepieces and which way one is swapping. Most of the 34mm show off axis ca with a 400 head and 181 eyepieces. The 40x .80 planapo without correction collar becomes particularly picky about it's cover slip thickness. Generally, the better corrected the objective is, the worse it is, probably because the expectations are higher.

Going the other way is a bit easier but still in my opinion , the peripheral corrections are inadequate. The Neoplans become less plan, some of the planachros are o.k and surprisingly a couple of the planapos, not too bad but there is ca , where it should not be, however minimal sometimes.

Best swap heads with the objectives.

Regarding the nosepieces. I never tried but I think a 400 series would not physically fit under the arm of a 10/20, if it is even the same dovetail. I never had one off, just the 6 place Diastar , which is on an Akehurst slide but the base is a round dovetail, so you could put a 6 place on a 410. Might do on a 100 series too and a 100 series nosepiece will fit a 10/20. That's the best way to get a 5 hole on one of those because the 5 place series 10/20 nosepieces are kind of scarce. The dovetail is 1/1/2" , not 2". The series 4 was 2".

geo_man
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Re: AO Triocular vs Beam Splitter

#16 Post by geo_man » Wed May 20, 2020 8:56 am

Many thanks for the great info, Phil!

apochronaut
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Re: AO Triocular vs Beam Splitter

#17 Post by apochronaut » Wed May 20, 2020 10:52 am

I neglected to point out that the effects on various objectives are not uniform. With the planapos for instance, probably due to their image circle being more homogeneously corrected , the malcorrections with the wrong telan lens introduces ca across the field, which increases in intensity with cover slip thickness. As an example a 25X .65 planapo viewed through the incorrect telan lens, which when viewed under it's well corrected condition would have virtually zero ca across the field , exhibits a decided pink interspacial ca; in clear cell walls for instance of about a micron, or between diatom striae of the same width. This is uniform and regular, and just resembles the performance that some achromats would give under normal conditions. Someone viewing the scene and not knowing that the objective was a planapo, would just see it as a microscope image. It looks fairly normal, except for the fact that the ca should not be there, in this case.

geo_man
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Re: AO Triocular vs Beam Splitter

#18 Post by geo_man » Wed May 20, 2020 7:16 pm

Interesting and thanks Phil. One last question on the nosepieces. I connected a 110 nosepiece to a model 10 scope and while it seemed to fit, it didn't properly align with the field diaphragm (too far off to center it). And the single bolt I loosened didn't travel in as far as it did on the native nosepiece. Do you think I don't have it seated properly our would all three bolts need to be adjusted to properly set the 110 nosepiece? Thanks again!

apochronaut
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Re: AO Triocular vs Beam Splitter

#19 Post by apochronaut » Wed May 20, 2020 8:16 pm

Take off the head and looking down through the yoke, center the nosepiece visually. The length of the three screw thread sections can be used as a guide. Make them as equal as possible. The first order of business is to center the nosepiece to the optical tube. Everything else aligns to that. Do you have a bertrand lens or a phase telescope?

apochronaut
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Re: AO Triocular vs Beam Splitter

#20 Post by apochronaut » Wed May 20, 2020 8:20 pm

A centering of the ilumination system is critical to centering the entire system, if you don't have any additional tools like a phase telescope or a centering objective.
Last edited by apochronaut on Wed May 20, 2020 8:23 pm, edited 1 time in total.

geo_man
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Re: AO Triocular vs Beam Splitter

#21 Post by geo_man » Wed May 20, 2020 8:22 pm

Thanks, and yes I have a phase telescope.

apochronaut
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Re: AO Triocular vs Beam Splitter

#22 Post by apochronaut » Wed May 20, 2020 8:42 pm

So, take out your condenser , put the head back in and turn the illuminator on. Using the phase telescope, and a representative phase objective ( I use a 40X, as long as it is very well centered with the 100X....whichever one you have that is is best), look through it at the phase annulus. There will be a series of concentric rings, inside or overlapping the image of the annulus. As you turn the nospiece lockscrews, you will be able to move those rings into the center of the annulus. The nosepiece will be pretty dead center. You just have to parcenter the objectives. There will be one position of the 5 which allows whatever small variances exist between the objective machining and the nosepiece machining, to cancel each other out somewhat. I aim to get the 40X and the 100X as close as possible. You may want to recheck the nospiece centring with the 40X annulus.

At this point too, you can use the 10X objective to view the illuminator window with the phase telescope. If the window doesn't have the brightest most symmetrical image, you may need to do some centering there too.

Lastly, install the condenser and set it up properly.

geo_man
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Re: AO Triocular vs Beam Splitter

#23 Post by geo_man » Wed May 20, 2020 8:50 pm

Thanks Phil. I’ll give it a try!

Zuul
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Re: AO Triocular vs Beam Splitter

#24 Post by Zuul » Wed May 20, 2020 10:33 pm

Ok, now I'm curious. What would the procedure be without a phase telescope? Eyeball it and call it good because that means you probably aren't doing phase anyway? ;)

apochronaut
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Re: AO Triocular vs Beam Splitter

#25 Post by apochronaut » Wed May 20, 2020 11:09 pm

Without a crosshair objective or phase telescope , eyeballing is probably fine. First, get the objectives as parcentered in the nosepiece as much as possible. I try to get within 10 microns for the 100X but 20 or so is acceptable. Get the nosepiece centered by eyeballing from above as advised, then take out an eyepiece. Using the highest magnification objective that is as close as possible to the 100X for centering, look down the optical tube with one eye, while the illuminator is low. You will be able to obtain a ring of light glancing off the lip of the optical tube. When that ring is very even in intensity, the illumination spot should be dead center. You can adjust it by moving the nosepiece back and forth as you look down the tube. You should get it pretty close. Center the illuminator, then the condenser. Make sure the objectives are level with the stage.

Really good images can be had with the alignment out somewhat but it can become a problem with higher N.A. objectives. I have noticed that the phase image is dramatically affected by alignment. I go to the length of shimming phase objectives into absolute alignment in the nosepiece. Once done, it is good for ever and even on a 60 year old microscope, I can swap nosepieces with little alignment variance.

geo_man
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Re: AO Triocular vs Beam Splitter

#26 Post by geo_man » Thu May 21, 2020 6:45 pm

Well I had some success I think, but I really couldn't recognize the concentric rings per Phil's guidance. I'm not sure if I was focusing the telescope at the right level, but I did move it up and down. Probably there but I just didn't see them. I pushed ahead anyway by adjusting the field diaphragm to about in the middle of its adjustment range and then I adjusted the 3 lock screws until the diaphragm image was centered. It seems fine to my relatively untrained eyes. I got this particular model 10 for $39, which included shipping! It's quite nice! Regards to all.

apochronaut
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Re: AO Triocular vs Beam Splitter

#27 Post by apochronaut » Fri May 22, 2020 2:50 am

That sounds about right. Using the field diaphragm is good. The 10 has a fairly narrow optical tube, barely able to clear 20mm. People sometimes forget that the design is 60 years old, when 20mm was a lot. For this reason, when a 100X objective is used with the 19mm eyepieces( 176), just about the entire optical tube is needed, so having the 100X particularly well aligned, limits the diffraction that can occur towards the periphery of the image. It's the objective, telan lens alignment particularly. A mild case shows as a lowered illumination on one side; users usually think it is an illuminator alignment issue but it is diffraction. I .have seen some where there was actually vignetting occurring on one side. It only shows with the 100X. The lower power objectives use a smaller diameter of the telan lens.

Zuul
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Re: AO Triocular vs Beam Splitter

#28 Post by Zuul » Fri May 29, 2020 4:01 am

I now have a 1043 trinoc head and there is a Nikon T-mount adapter on its way. The phototube is the last piece I need.

Today I realized that my condenser is a simple Abbe. It’s only marking is “N.A. 1.25” so I believe it’s a 1088, but I’m not certain. For reasons I can’t explain, I happen to have a 1087 condenser on hand. It’s just the top threaded portion, though, and the threads are smaller than what is on my iris body. The optics themselves appear to be identical in diameter. I’m tempted to try swapping the 1087’s lenses into the 1088’s body so it can be threaded into the iris/dovetail.

apochronaut
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Re: AO Triocular vs Beam Splitter

#29 Post by apochronaut » Fri May 29, 2020 11:01 am

Yes. If one of those older condensers is just marked 1.25, then it is a two lens abbe. The 1087 is also a two lens but the bottom lens is noticeably aspheric. I suspect that the front lens is the same on each, since the 1.25 N.A. specification is established by it's angle, so theoretically an interchange of the bottom lens is possible. The critical dimension is the distance from the bottom center of the front/top lens to the top center of the bottom lens. I can't remember whether this is established by a shoulder in the condenser body on each of them or a combination of shoulder and spacer. It's been a while since I cleaned either of them. If a spacer is involved , you may be able adjust the distance down, if it turns out that the aspheric lens is too far away in the 1088 body, or alternately up by creating a thin additional shim. In DIY condensers that I have built using existing bodies, I found that rubber o-rings make usefull spacers/shims. On might also be able to cut thin ones from large plastic bottle caps, tin cans etc., or with luck find a bottle cap liner seal of the correct size. Very thin washers with very wide i.ds and a minor differential between the i.d. and o.d. are almost impossible to find. Such are sometimes used in electric motors.
The aspheric lens is critically shaped and spaced in order to limit peripheral ca, the most glaring deficiency of an abbe, so keeping it's correct distance from the top lens is very important.

Zuul
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Re: AO Triocular vs Beam Spli

#30 Post by Zuul » Sat May 30, 2020 10:34 pm

apochronaut wrote:
Fri May 29, 2020 11:01 am
Yes. If one of those older condensers is just marked 1.25, then it is a two lens abbe. The 1087 is also a two lens but the bottom lens is noticeably aspheric. I suspect that the front lens is the same on each, since the 1.25 N.A. specification is established by it's angle, so theoretically an interchange of the bottom lens is possible. The critical dimension is the distance from the bottom center of the front/top lens to the top center of the bottom lens. I can't remember whether this is established by a shoulder in the condenser body on each of them or a combination of shoulder and spacer.....
I opened the 1087 and the spacing is set by a shoulder machined into the body. As such, I’ve decided to skip trying that DIY. The biggest problem being I don’t have enough experience to judge the success or failure of the results. Oh well. Future upgrade.

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