MicrobeHunter.com Microscopy Forum

Looking for a triangular head for the CORRECT TOKYO SEIWA OPTICAL.

Regards

Trinocular?
Bear with me for asking - is it to replace the AO? because there are great AO expert members of this forum.

The AO head has a lens in the bottom to converge the infinity beam. The optics are unlikely to work well on your Correct microscope. From the details of construction on your Correct microscope, objective design, head, stage, it looks to be a stencil made by Kyowa. Similarly to the current Chinese situation, several Japanese mfg. did stencil branding for other companies. Kyowa and Carton were two of the more prominent ones.
Since the AO head, which has a 2" dovetail fits( or does it just sit on top?), you have a fairly large dovetail. Look for a Kyowa or other trino head. Correct did have trinos. but they are going to be hard to find. The company seems to have morphed into industrial microscopes, with objectives that are almost identical to Mitutoyo, possibly even made by them.
Firstly, measure your dovetail accurately, then see what exists that would fit. Kyowa, Meiji maybe, Swift?, Bristol, Unitron, there are others too.

The trinocular head dovetail


Regards

Please Forum administrator change the title of this thread to TRINOCULAR HEAD FOR CORRECT TOKYO SEIWA MICROSCOPE

The dovetail is the larger section above it. That is a traveling tube lens, which raises and lowers in order to maintain focus during diopter adjustment. You are measuring the lens housing extension in the picture.

Apochronaut thank you for your time (and patience) in this matter.

Let see if get it right. The height is 9mm as you can see in the picture:


Regards

Apochronaut I have made the following test:

Pictures with 4x 10x 40x 100x objectives. Mosquito wings 12mm closer to the objective with a glass above the stage unit.


Would it be a good solution to buy parfocal length extenders if I am not able to find a proper trinocular head?



Regards

I forgot to say that those pictures were taken through one of eyewievs.


Regards

Trinocular pictures...


Regards

It's not an issue of the actual tube length, it is that the AO tube lens does make some corrections for the infinity corrected objectives, that probably overcorrect for your objectives. The 10X image is not too bad but I do see increasing chromatic aberration as well as spherical aberation with the higher magnifications. I'd be looking for a Japanese finite tube head.

apochronaut wrote:It's not an issue of the actual tube length, it is that the AO tube lens does make some corrections for the infinity corrected objectives, that probably overcorrect for your objectives. The 10X image is not too bad but I do see increasing chromatic aberration as well as spherical aberation with the higher magnifications. I'd be looking for a Japanese finite tube head.

Thanks again apochronaut, I am searching for a Japanese finite tube head, nothing available. Not even those you suggested Kyowa, Meiji, Swift, Bristol or Unitron, as you said 'hard to find'. Any other brand?


Regards

In the two set of pictures sent the last ones are 4X (sorry for the mistake).


Regards

Apochronaut, In the case I wouldn't be able to find a finite trino, would be a good idea to take the corrective lens of the AO trinocular?

Regards

You might be able to remove that lens and have it work. The tube length of the AO system is supposed to be 200mm but as an infinity system. I never thought through the implications of removing the tube lens.It also travels, so you would lose the distance compensation for the diopter width.

I like D.I.Y. solutions, if they are likely to be fairly slick and functional but with this one, I am unsure. I wouldn't risk damaging that head. Isn't there someone looking for one on the forum? It might be better to sell that one and put the money towards one that would be an actual functioning unit. Finding the right part for used microscopes often takes a little patience.

How does the head attach to your microscope? Is it a threaded ring, with a dovetail or a dovetail with a locking screw or other? I can't tell from your pictures. It looks to me that when you set the AO head over the yoke of the microscope, that just the lens housing extension, the 1.6" diameter section that you measured is nesting in, with the actual 2" dovetail resting on top. Can you provide the actual measurements and physical attachment design? Someone might have something that will fit, or at the very least, the actual possibilities gleaned from other brands could be isolated.

apochronaut wrote: How does the head attach to your microscope? Is it a threaded ring, with a dovetail or a dovetail with a locking screw or other? I can't tell from your pictures. It looks to me that when you set the AO head over the yoke of the microscope, that just the lens housing extension, the 1.6" diameter section that you measured is nesting in, with the actual 2" dovetail resting on top. Can you provide the actual measurements and physical attachment design? Someone might have something that will fit, or at the very least, the actual possibilities gleaned from other brands could be isolated.

Fits perfectly inside.

stjepo wrote:

apochronaut wrote: How does the head attach to your microscope? Is it a threaded ring, with a dovetail or a dovetail with a locking screw or other? I can't tell from your pictures. It looks to me that when you set the AO head over the yoke of the microscope, that just the lens housing extension, the 1.6" diameter section that you measured is nesting in, with the actual 2" dovetail resting on top. Can you provide the actual measurements and physical attachment design? Someone might have something that will fit, or at the very least, the actual possibilities gleaned from other brands could be isolated.

Fits perfectly inside.

54mm dovetail. Quite large actually.

I understand.

Yes the: '1.6" diameter section that you measured is nesting in, with the actual 2" dovetail resting on top.' ' just the lens housing extension' fits in.


Regards

stjepo wrote:I understand.

Yes the: '1.6" diameter section that you measured is nesting in, with the actual 2" dovetail resting on top.' ' just the lens housing extension' fits in.


Regards

This one https://www.ebay.ca/itm/332684273311?ul_noapp=true, has a 50mm dovetail and the center relief is 30mm. Good price.

You might seek some further info. from the seller, though. It looks like he might have measured the dovetail pictured and there probably is another one under the head. The head itself looks to be Olympusish, so the dovetail might be around 40mm.

apochronaut wrote:

stjepo wrote:I understand.

Yes the: '1.6" diameter section that you measured is nesting in, with the actual 2" dovetail resting on top.' ' just the lens housing extension' fits in.


Regards

This one https://www.ebay.ca/itm/332684273311?ul_noapp=true, has a 50mm dovetail and the center relief is 30mm. Good price.

You might seek some further info. from the seller, though. It looks like he might have measured the dovetail pictured and there probably is another one under the head. The head itself looks to be Olympusish, so the dovetail might be around 40mm.

Thank you apochronaut, I will see to it.

I think that the trinocular will not be my biggest problem, I have made the following test with the settings shown in the picture. 170 mm from the stage to the camera tube. It seems that I need better finite objectives, but which ones or maybe a better microscope...

I would not blame the objectives yet, except perhaps the 100X.
As I see it:
The 4X photo - insufficient illumination across the FOV, did you use a condenser?
The 10X seems nice to me.
The 40X photo - low contrast. Again - did you use a condenser? Kohler illumination? was the condenser iris stopped down to increase contrast?
The 100X - same as the 40X, but some chromatic aberration as well.
The selectively sharp "hairs" in photos 40X and 100X are perhaps due to the shallow depth of focus. Are these single frames?

Thank you very much for your answer Hobbyst46:

Hobbyst46 wrote:I would not blame the objectives yet, except perhaps the 100X.
As I see it:
The 4X photo - insufficient illumination across the FOV, did you use a condenser?

Yes I did.

Hobbyst46 wrote:
The 40X photo - low contrast. Again - did you use a condenser? Kohler illumination? was the condenser iris stopped down to increase contrast?

Yes I used a condenser but I doubt that this microscope is prepared for Kohler illumination (neither I am) my light is a simple led that comes from the illuminator.
The condenser iris was wide open. (I will start using it)

Hobbyst46 wrote:
The selectively sharp "hairs" in photos 40X and 100X are perhaps due to the shallow depth of focus. Are these single frames?

Yes single frames...

Go back to repeat the test.

Indeed, Kohler illumination is set-up with a field diaphragm. When it is absent, some alternative tricks were suggested but I do not know how effective they are.
Please, do stop down the condenser iris, it definitely improves the image.

Yes it does, thanks for the tips.

Regards

Hopefully you can find a trinocular head for this scope at a reasonable price. Otherwise, like 75RR and others suggested, I would not invest in better objectives for this scope; rather, enjoy it as it is, find interesting subjects, and in the meantime, patiently locate a good trinocular microscope, for which parts are available, and upgrade.
Good luck!

Hobbyst46 wrote:Hopefully you can find a trinocular head for this scope at a reasonable price. Otherwise, like 75RR and others suggested, I would not invest in better objectives for this scope; rather, enjoy it as it is, find interesting subjects, and in the meantime, patiently locate a good trinocular microscope, for which parts are available, and upgrade.
Good luck!

Very good advice!!! And thanks for your patience

Regards

Now the last advice to all of you.

Could you give me a list of brands and models of microscopes that I should buy to improve the quality of the images?

I know there are many, but must be some that, because your large experience, you might think will be better.

Regards

The type of objectives that you have are the most common type produced in Japan over a long period: achromats. Yours look to either Kyowa or Meiji but similar type objectives produced by Carton, Fuji, Olympus or Nippon Kogaku would all perform similarly, although some might be slightly superior for various reasons. Kyowa made objectives for many customers for many years, as well as under their own name and their optical quality is excellent. I have a Kyowa microscope with objectives virtually identical to yours, only marked Kyowa. They perform beautifully for what they are; achromats.
For photographic purposes, those conventional achromats are unsuitable because they exhibit too much lateral ca, curvature of field and sometimes even flare or coma. That's why with older photo systems compensating eyepieces were recommended and the image captured was only a small central part of the total field. As plan objectives came along, those problems of lateral ca and others, became less and one was able to capture a larger total, flat field, with better edge definition. Better yet would be plan fluorite or planapo objectives but one loses some working distance increasingly with higher N.A., so samples need to be more precise and the higher magnification fluorites and apochromats often , can not be focused at all with cheaper prepared slides due to excessive slide thickness.

I would be looking for a short tube set of plan objectives. They will be unlikely to provide better central image performance but the periphery of the field will be better for photos. Very few companies offered plan objectives in the J.I.S. short tube format. Almost all you would see, would be either Olympus or Nikon. I haven't seen short tube Meiji plan objectives, all I have seen were made after they converted to D.I.N. 160mm but they continued to make optics for science supply houses and the like, after that; Cenco, NorthWest etc. You could improve the microscope with a set of J.I.S. plan objectives but they are hard to find and seldom at a good price.

Other option would be to sell it as is and get a used trinocular system with plan objectives. Since you have an AO 10 head, you could probably land an AO 10 frame really cheaply. AO planachro objectives are really easy to find. That's a pretty easy microscope to get up to a quality functional photo system, with superior optics.

apochronaut wrote:The type of objectives that you have are the most common type produced in Japan over a long period: achromats. Yours look to either Kyowa or Meiji but similar type objectives produced by Carton, Fuji, Olympus or Nippon Kogaku would all perform similarly, although some might be slightly superior for various reasons. Kyowa made objectives for many customers for many years, as well as under their own name and their optical quality is excellent. I have a Kyowa microscope with objectives virtually identical to yours, only marked Kyowa. They perform beautifully for what they are; achromats.
For photographic purposes, those conventional achromats are unsuitable because they exhibit too much lateral ca, curvature of field and sometimes even flare or coma. That's why with older photo systems compensating eyepieces were recommended and the image captured was only a small central part of the total field. As plan objectives came along, those problems of lateral ca and others, became less and one was able to capture a larger total, flat field, with better edge definition. Better yet would be plan fluorite or planapo objectives but one loses some working distance increasingly with higher N.A., so samples need to be more precise and the higher magnification fluorites and apochromats often , can not be focused at all with cheaper prepared slides due to excessive slide thickness.

I would be looking for a short tube set of plan objectives. They will be unlikely to provide better central image performance but the periphery of the field will be better for photos. Very few companies offered plan objectives in the J.I.S. short tube format. Almost all you would see, would be either Olympus or Nikon. I haven't seen short tube Meiji plan objectives, all I have seen were made after they converted to D.I.N. 160mm but they continued to make optics for science supply houses and the like, after that; Cenco, NorthWest etc. You could improve the microscope with a set of J.I.S. plan objectives but they are hard to find and seldom at a good price.

Other option would be to sell it as is and get a used trinocular system with plan objectives. Since you have an AO 10 head, you could probably land an AO 10 frame really cheaply. AO planachro objectives are really easy to find. That's a pretty easy microscope to get up to a quality functional photo system, with superior optics.

Apochronaut, is the best advice I have ever received. In few words you have shown my options, thank you for your time, I appreciate it.
Regards

I came across this. Checked on the shipping and it is $55.00 U.S. to Spain. There may be some fees payable to Spanish Customs too. Might depend on how well you do in the World Cup.

It has 4 planachros. It's all there but a transformer. AO sold a 220 v. version of the transformer for that to Reichert, which they used as their 6v. trafo for a while. You might get lucky and find that one in Europe somewhere but any 6V. trafo will do, with a plug change on the illuminator connector cord.

The photo tube for your trinocular head is 28.00 + shipping on ebay right now. The rest of the parts to get to a bayonet for your camera will run around 20.25.00 U.S. An eyepiece for the photo tube is 50-75.00. They are fairly common on ebay. I have one if you need it.

https://www.ebay.ca/itm/311984046126?ul_noapp=true

apochronaut, he has accepted my offer. Hmmm... I am scared... (also I am looking a BX51. Is it good?)

I keep you posted...


Regards