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Olympus part?, identification.
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ChrisR
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PostPosted: Tue Jun 09, 2015 7:54 pm    Post subject: Olympus part?, identification. Reply with quote

This part fits has no name or designation. Some things I can work out, but I may be wrong?

It
Fits an Olympus BH stand, above the turret,
Has an analyzer on a slider, shown half retracted,
Has a small hole, on another slider
Contains a lens which appears to be their 180mm or thereabouts, focal length.
Has a slot for a slider, here shown with the silver ring twisted to half-close it.

I can't find this part on the pdf files from Alan Wood's site
I assume it's for infinite objectives?, was it an optional part to convert a finite setup on a BH(x) to infinite? But which one?
I assume the half-covered slot is for retarders etc?

There were two ranges of Oly infinite objectives. The earlier range needed eyepiece correction for CA. Did they use the same "tube" lens?

And, what's the little hole for? Aligning something?



Edit - more questionmarks added!


Last edited by ChrisR on Wed Jun 10, 2015 2:25 am; edited 1 time in total
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Pau
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PostPosted: Wed Jun 10, 2015 1:18 am    Post subject: Reply with quote

I don't know this part but it seems the typical pol intermediate piece used in microscopes of its era. Those pieces have a Telan lens system (the lenses at both ends of the piece) designed to maintain the tube length in finite microscopes, not needed in infinite designs
Are you sure that it is an Olympus part? The construction seems to better match a Zeiss Jena design

The slot is very likely intended to put compensators (wave plates) and the lens could be a Bertrand lens intended to provide conoscopic image, that means to see the rear focal plane of the objective (and its conjugate planes), very useful in crystal optical properties analysis. The hole would be to improve the conoscopic image contrast.
You can test my hypothesis:
- Set the microscope to Kölher with a 40X objective with a sample slide. The field aperture diaphragm on the light source will be visible if closed
- Slide in the mystery lens. Now the image will be totally defocused.
- Close the condenser aperture diaphragm, now it will be visible while the field aperture diaphragm do not.

The Bertrand lens is also useful to properly set the microscope for phase contrast, DIC and other optical contrast techniques
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ChrisR
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PostPosted: Wed Jun 10, 2015 2:52 am    Post subject: Reply with quote

What you're sayiing is consistent with its source - a box of old odds and ends.
I was thinking Olympus because it apparently fits the dovetail - were they the same? [Edit - no, it doesn't quite centre correctly]
I don't have anything else that might be Zeiss.

A Google image search on "Zeiss Bertrand Lens" brings up a picture of an identical device, which leads to an expired ebay sale from a vendor who appears to know about what he sells. The picture only remains in Google's cache:
If this works: http://tinyurl.com/q23w9k2

It was ebay item 181161665920
Carl Zeiss Jena Laboval Polarizing Microscope Analyser Unit with Bertrand Lens

Thanks!

Unfortunately it's of no use to me, though I might take the polarizer out.
It's intriguing that the focal length of the assembly is about right for a "tube" lens; I used distant street lights at night, focused on a white vehicle, to guesstimate the FL.
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Ichthyophthirius



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PostPosted: Thu Jun 11, 2015 6:56 am    Post subject: Reply with quote

ChrisR wrote:
Unfortunately it's of no use to me, though I might take the polarizer out.


Really? A polariser you can get cheaper elsewhere.

This unit has a focussable Bertrand lens for a polarising microscope. It's very useful for conoscopy (mineralurgical microscopes) or even just for setting up phase contrast or DIC.

It's hard to get a unit like this (polariser and Bertrand lens) from other manufacturers. The similar Zeiss West unit costs around £300 on Ebay.

The lower lens is either the tube lens (for correcting the change in tube length from 160 mm through the intermediate tube) or the lower Telan lens (I can't tell from the images).

Better sell it on. It will make a mineralogist very happy.

Regards, Ichthy
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ChrisR
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PostPosted: Thu Jun 11, 2015 9:20 am    Post subject: Reply with quote

Now you're making me feel ashamed Embarassed
It is nicely made - in the "they don't make things like this any more, or if they do I can't afford it", bracket.

I happen to need a pol for a Nikon head about 21mm diameter and there aren't any around at the moment. Left side, a rather cheap looking unZeiss carrier:

The lower lens - would it be negative for Telan and positive for "tube"?

Ebay it may be then.
It's a pity it's for a rather old 'scope or I'd keep it until my knowledge catches up.


Last edited by ChrisR on Tue Dec 19, 2017 3:30 am; edited 1 time in total
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Ichthyophthirius



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PostPosted: Thu Jun 11, 2015 12:02 pm    Post subject: Reply with quote

ChrisR wrote:
It's a pity it's for a rather old 'scope or I'd keep it until my knowledge catches up.


Hi Chris,

The microscope (this would have been the "Laboval 5") is still made today http://www.askania.de/data/index.php?option=com_content&task=view&id=91&Itemid=122 Wink

The pol intermediate tube will fit all the gray Zeiss Jena 160 mm microscopes (upright stands), like Laboval, Ergaval or Amplival. It would be handy for anybody who uses these stands for phase contrast, as the Bertand lens makes the adjustment easy (no telescope necessary) if it is indeed focussable.

It was used for the "simpler" petrographic microscopes like this Laboval http://earth2geologists.net/Microscopes/photogallery/Zeiss_aus_Jena.JPG but it will also fit the larger stands.

The lower lens should be negative if it is a simple tube lens. If it is a Telan system, the lower lens should be negative and the upper lens should be positive: http://www.microscopy-uk.org.uk/mag/imgjun12/Top-004.bmp.jpg

Kind regards, Ichthy
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g4lab



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PostPosted: Thu Jun 11, 2015 12:02 pm    Post subject: Reply with quote

The Laboval series used 160mm tl lenses. They were not infinity lenses.
and Zeiss Compens series oculars with a reddish or yellow orange chromatic edge in the ocular field diaphragm.

The build quality was not up to Zeiss West Germany and E. Leitz standards.
It was comparable to Japanese scopes of the sixties and seventies.
Sometimes they didn't get certain things right. Usually centration, and plastics selection.
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Ichthyophthirius



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PostPosted: Thu Jun 11, 2015 12:14 pm    Post subject: Reply with quote

ChrisR wrote:
I happen to need a pol for a Nikon head about 21mm diameter and there aren't any around at the moment.


21 mm slider width or polariser diameter?

How about this 20 mm polariser as a replacement? http://www.edmundoptics.co.uk/optics/polarizers/linear-polarizers/high-contrast-plastic-linear-polarizers/85918/
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Ichthyophthirius



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PostPosted: Thu Jun 11, 2015 12:27 pm    Post subject: Reply with quote

g4lab wrote:
and Zeiss Compens series oculars with a reddish or yellow orange chromatic edge in the ocular field diaphragm.


Compensating eyepieces (K and PK) for plan achromats, apochromats and high magnification achromats. Non-compensating eyepieces (A and later P) for low magnification achromats.

However, there was also a series of achromats for 160 mm tubes length (10 to 100) that were "colour free", just like the Nikon CF series (Nikon and Zeiss Jena independently started making them around the same time).

Regards, Ichthy
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ChrisR
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PostPosted: Fri Jun 12, 2015 3:19 am    Post subject: Reply with quote

Would glass be better? (I thought plastic would be for an illumination source)
Anyway they do these in glass http://www.edmundoptics.co.uk/optics/polarizers/linear-polarizers/mounted-linear-glass-polarizing-filters/1396/ which I think could be made to fit.
I fancy making it rotatable, with a couple of wheels, in a plastic or brass section. The OD is approximately 24 x 5.5mm.
The Nikon one is quite expensive:
http://www.ebay.co.uk/itm/Nikon-Microscope-Rotatable-Epi-Analyzer-for-Microphot-/271740077430?pt=LH_DefaultDomain_0&hash=item3f44f88576
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Pau
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PostPosted: Fri Jun 12, 2015 5:38 am    Post subject: Reply with quote

This one seems much better (likely at the Nikon level*), see the specifications:
http://www.edmundoptics.co.uk/optics/polarizers/linear-polarizers/unmounted-linear-glass-polarizers/47315/

The plastic one also seems very nice and much less expensive, but I don't know for sure

You really don't need the analyzer to be rotatable, just to be able to rotate it while setting up the system. If the reflected DIC system is mounted in the standard position, the analyzer just needs to be mounted in N-S direction, just following the long direction fo the slider. For cross pol you just need one of the filters to be rotatable, although to have both rotatable may be nice in some cases

* I have a very good Nikon analyzer and a Edmund's similar to the one I linked (they were sold under their Techspec brand but the specification is the same) and both work equally well por cross pol and DIC. Almost for sure it will be also better than the old Zeiss Jena
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ChrisR
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PostPosted: Fri Jun 12, 2015 6:04 am    Post subject: Reply with quote

Yes I did $ee that one!
I hope to be able to put a variety of objectives on this Nikon, and won't be generally using the incident lighting attachment as a light source. So if, eg, I'm using a polarizing sheet over Ikea Janjos, it would be easier to turn the analyzer.
I'm dissuaded from investing in incident DIC parts, and so far, this 'scope (Measurescope UM-2) doesn't have a condenser.
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Ichthyophthirius



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PostPosted: Fri Jun 12, 2015 7:43 am    Post subject: Reply with quote

ChrisR wrote:
Would glass be better? (I thought plastic would be for an illumination source)
Anyway they do these in glass http://www.edmundoptics.co.uk/optics/polarizers/linear-polarizers/mounted-linear-glass-polarizing-filters/1396/ which I think could be made to fit.
I fancy making it rotatable, with a couple of wheels, in a plastic or brass section. The OD is approximately 24 x 5.5mm.


Hi Chris,

I linked the plastic version as it should be a usable compromise. The TechSpec polariser (same as used in Pau's glass version) has better extinction than the glass polariser you linked to but for the same price. As long as you don't clean the surface regularly, it should be OK.

For a homemade rotation device, see here for one made from clock gears http://www.mikroskopie-forum.de/index.php?topic=12778.0 ; however, the shape of the gears seems to be important, so there isn't too much "play" in the system. Nowadays you might be eable to 3D print the whole thing!

Regards, Ichthy
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Pau
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PostPosted: Fri Jun 12, 2015 8:10 am    Post subject: Reply with quote

Quote:
So if, eg, I'm using a polarizing sheet over Ikea Janjos, it would be easier to turn the analyzer.


If you use more than one external light source you need to have the polarizers rotatable. Take a look to my macro setup, first and third images, the analyzer is not rotatable but the polarizers are

http://www.photomacrography.net/forum/viewtopic.php?p=67184#67184
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ChrisR
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PostPosted: Fri Jun 12, 2015 10:09 am    Post subject: Reply with quote

I like the wooden one, By Appointment to Her MajestySmile I'm sure she's a discerning user.
I had a few ideas, as one does, eg using a speedometer cable crown wheel and pinion , but my eyes came to rest on a bust mouse's rubber coated wheel.
That could be the one in the middle, with an ebay plastic gear wheel to the left, and a couple of brass tube-over-rod rollers in the corner.
This I could do with simple tools. Excuse the sketch - 3 mins in MS Word.



I'll be measuring sections of all sorts etc, for something the right starting size. 5 x 24mm approx.

I can think of other ways, with threaded rod as a worm drive, etc. I don't think I need any great precision.

it would be intrtesting to find out first, perhaps by tilting a piece of glass, whether reflections are a problem.
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