Infinity objectives, Orthoplan

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Rorschach
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Infinity objectives, Orthoplan

Post by Rorschach »

This question may once more expose how little I know yet about matters related to compound microscopes. But I will ask it nevertheless.

So I have an Orthoplan with an 0.8x infinity nosepiece that is intended for reflected light work. Why can't I use infinity transmitted light objectives on it, provided that I am using the appropriate condenser (and, obviously, transmitted light)?

Edit: typo
Last edited by Rorschach on Tue May 12, 2020 6:02 am, edited 2 times in total.

Pau
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Re: Infinity objectives, Orthoplan

Post by Pau »

Rorschach wrote:So I have an Orthoplan with an 0.8x infinity nosepiece that is intended for reflected light work. Why can't I use infinity transmitted light objectives on it, provided that I am using the appropriated condenser (and, obviously, transmitted light)?
Have you tried it?
I don't know the focal length of the tube lens (if mounted inside the nosepiece you could be able to approximately determine it) but because AFAIK they still used Periplan compensating eyepieces I think that the tube lens is not compensating like in modern Leica and Zeiss instruments and so you must be able to work with modern Olympus UIS or UIS2 objectives or Nikon CF infinites, and CFI 60 with an adapter and if you if you have enough place
Pau

Rorschach
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Re: Infinity objectives, Orthoplan

Post by Rorschach »

Pau wrote:
Rorschach wrote:So I have an Orthoplan with an 0.8x infinity nosepiece that is intended for reflected light work. Why can't I use infinity transmitted light objectives on it, provided that I am using the appropriated condenser (and, obviously, transmitted light)?
Have you tried it?
I don't know the focal length of the tube lens (if mounted inside the nosepiece you could be able to approximately determine it) but because AFAIK they still used Periplan compensating eyepieces I think that the tube lens is not compensating like in modern Leica and Zeiss instruments and so you must be able to work with modern Olympus UIS or UIS2 objectives or Nikon CF infinites, and CFI 60 with an adapter and if you if you have enough place
Not yet. I am still lacking a trinocular, as the one I got was quite hopelessly stuck (inter-ocular distance). I have a good trino being shipped to me so after a while can perform this test for example.

What you write, confirms my thinking. Since Periplan compensating eyepieces were required, the tube lens probably does none of the compensating.

I have a few Reichert infinity lenses so I'll test on those once the system is complete. Of course, with the 0.8x nosepiece, one loses magnification but gains in field of view. The extra field only helps if the objectives are corrected for planarity wide enough, of course. And I suppose I need to use non-correcting eyepieces of 30mm diameter, such as Wild stereo eyepieces.

Ichthyophthirius
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Re: Infinity objectives, Orthoplan

Post by Ichthyophthirius »

Rorschach wrote:Of course, with the 0.8x nosepiece, one loses magnification but gains in field of view. The extra field only helps if the objectives are corrected for planarity wide enough, of course.
Hi,

Do you really need extra field of view? If you have a 1x nosepiece for transmitted light, you can get FN28 with Leitz' own objectives and eyepieces. The Periplan GW 8x has a field number of 28, giving you the same field and magnification as you try to achieve with the 0,8x/∞ nosepiece. https://www.ronaldschulte.nl/files/Manu ... plan78.pdf Leitz Pl and Pl Apo are corrected for FN 30.

You can also use Leitz metallographic objectives with the 0,8x/∞ nosepiece for low magnification or without a cover glass for high magnifications.

Regards, Ichty

Rorschach
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Re: Infinity objectives, Orthoplan

Post by Rorschach »

Ichthyophthirius wrote:
Rorschach wrote:Of course, with the 0.8x nosepiece, one loses magnification but gains in field of view. The extra field only helps if the objectives are corrected for planarity wide enough, of course.
Hi,

Do you really need extra field of view? If you have a 1x nosepiece for transmitted light, you can get FN28 with Leitz' own objectives and eyepieces. The Periplan GW 8x has a field number of 28, giving you the same field and magnification as you try to achieve with the 0,8x/∞ nosepiece. https://www.ronaldschulte.nl/files/Manu ... plan78.pdf Leitz Pl and Pl Apo are corrected for FN 30.

You can also use Leitz metallographic objectives with the 0,8x/∞ nosepiece for low magnification or without a cover glass for high magnifications.

Regards, Ichty
Hi,

It's not really the extra field that I am after. It's more just a fact that I happen to have this reflected light nosepiece that is infinity and has 0.8x magnification factor. So if I succeed in using transmitted light infinity lenses on it (with the proper condensor), that's what I get: lowered magnification but wider field of view. This can be countered with the choice of Orthoplan eyepieces, I suppose (6.3x, 8x or 10x).

Ichthyophthirius
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Post by Ichthyophthirius »

OK, I understand. Then one more (potentially) useful bit of information: as far as I understand the literature, the ∞/0.8x nosepiece has a 200 mm tube lens (∞/1x is 250 mm). That's a bit more than Olympis UIS (180 mm) but the same as Nikon CFI60.

Rorschach
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Post by Rorschach »

Ichthyophthirius wrote:OK, I understand. Then one more (potentially) useful bit of information: as far as I understand the literature, the ∞/0.8x nosepiece has a 200 mm tube lens (∞/1x is 250 mm). That's a bit more than Olympis UIS (180 mm) but the same as Nikon CFI60.
Thanks Ichty! I need to find out what length tube lens would suit Reichert infinity and later Leitz infinity lenses.

This also generated the (heretic) idea of swapping a tube lens in a nosepiece to a different one. Has this been done by anyone and can it be successful? I assume the tube lenses are attached by a thread, not by adhesive. This of course assumes that the tube lens indeed does not perform any optical corrections. If that isn't true, then an 'alien' tube lens would induce aberrations.

Ichthyophthirius
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Post by Ichthyophthirius »

Hi,

Please don't :( They are not meant to be exchanged. It's likely to loose some kind of calibration and will make it useless in the future.

The 0.8x tube lens also has a very small diameter compared with current tube lenses. I agree with Pau; the tube lens doesn't compensate colour. It might therefore work with Olympus UIS and Nikon CFI60 objectives, which don't need colour compensation. Leica HCS objectives have their own, compensating tube lens.

Alternatively, Saul has shown a 3D printed tube lens adapter here https://www.photomacrography.net/forum/ ... p?p=246603 for a single objective.

If you want to use a revolving nosepiece, you could 3D print an adapter for any scrap microscope nosepice and adapt it like Saul did - doesn't seem necessary to sacrifice an Orthoplan part.

Regards, Ichty

Rorschach
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Joined: Fri Mar 08, 2019 11:35 pm
Location: Finland

Post by Rorschach »

Hi Ichty,

Ok, in that case I won't touch the tube lenses! :D I don't want to ruin these magnificent instruments. Wasn't aware of the consequences of removing or replacing a tube lens.

I guess I'm mostly intrigued by the possibility to use various infinite lenses on Orthoplan - something that was not supposed to be possible according to the gospel, apart from metallurgical reflected light objectives.

What really appeals here is the possibility to add YET more flexibility to an already astonishingly versatile and modular system!

Pau
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Post by Pau »

Be aware that the Orthoplan, being originally a 170mm corrected system and not a DIN one, needs Periplan eyepieces for 170 microscopes and with other brand objectives this can be problematic:

Leitz 170 system forms the primary image 18mm below the end of the eyepiece tube while DIN standard and most other systems do it 10mm bellow it, so you will have two options, none of them good:

- use Periplan eyepieces with objectives that do not need this correction inducing radial chromatic aberration

- use non compensating DIN or modern eyepieces, in which case you will have a 8mm increase of the mechanical tube length and optical issues like spherical aberration and lack of parfocality between objectives

I don't know about any non compensating eyepieces compatible excepted the poor and old Leitz Huygens type

other more complex options could be to adapt a Leitz Diaplan or Aristoplan head if possible or to cut the eyepiece tubes (not to be recommended!)

Maybe a normal 170 (finite) nosepiece and 170 biological objectives would be a better idea.
Pau

Ichthyophthirius
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Post by Ichthyophthirius »

This is not such a big problem. Shockingly, the Orthoplan actually has a 162 mm optical tube length.

It appears that the 30 mm diameter Periplan eyepieces have a 10 mm parfocal length. According to some sources they can be swapped against modern eyepieces with 10 mm parfocal length (DIN) without any problems.

There are Leitz eyepiece adapters for using 23,2 mm diameter Periplan eyepieces ("real" 170 mm optics, 18 mm parfocal length) (centre here: http://www.microscopy-uk.org.uk/mag/img ... 39794b.jpg ) These adapters add exactly 8 mm to the tube length: https://i.ebayimg.com/images/g/qRkAAOSw ... s-l500.jpg to make up for the difference.

So the Orthoplan allegedly has some hidden DIN characteristics. My own Orthoplan is still packed up so I've not been able to confirm that myself.

Regards, Ichty

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