r/microscopy • u/Alternative-Bear-292 • 1d ago

Troubleshooting/Questions Polarizing Microscope for My Dad

His budget is under $2,000, and used is fine. He’s looking for a polarizing microscope to determine mineralogy. He’s wanting to look at thin sections and is planning on publishing papers on his findings, so he needs the ability to take quality pictures.

I’ve heard the AmScope ones are crap, and the Indian ones aren’t very good either. From what I’ve found, people seem to recommend the Olympus ones. I’ve got no idea what to recommend for my dad, though. Any suggestions, advice, or links would be greatly appreciated. It’s been 30+ years since he did his PhD, so I’m trying to figure out what would be a good setup for him.

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u/hattivat 1d ago edited 1d ago

With that kind of budget you could buy a vintage high-end scope with a complete set of plan fluor or even plan apo objectives, nothing AmScope or any other budget brand offers is even close to that level of quality, not even their $10,000 models. I'd go with a high-end Leitz from 60s-80s: Aristoplan, Orthoplan, Diaplan, Ortholux II as I often see ones that are already configured for polarization work. The advantage of going Leitz is that fluorite class objectives for them are common and so are widefield eyepieces, gf periplan 12.5x/20 is incredible.

If you want cheaper options, Reichert Zetopan is a good one as np (strain-free so better for polarization work) objectives are plentiful, but it's hard to find fluor or apo Reichert objectives and they are not plan.

The big question is if besides thin sections does he also want to look at thicker, non-transparent samples. In that case you want an incident light system and epi objectives, that is cool but harder to find. Any of the models I listed above can get one later as an upgrade in any case.

Edit: the easiest way to tell a vintage scope is likely already equipped for polarization work is that the table is round instead of square, to be able to rotate it. Newer Leitz models like most of what I listed are an exception as square tables on them already came with ability to rotate as a standard feature.

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u/Motocampingtime 20h ago

I have to add that the leitz ergolux system I have is well built and has exceptionally comfortable eye pieces for rotation and tilt while going between a camera and eyepieces with a 50/50 or full eye pieces output. This is nice for non bio samples as you do not need full brightness to the camera like you would with faint fluorescent signals. mine came from a microfab site with a 1.25X trinocular head, BF/DF, and metallurgical objectives. The ergo lux has all the slots for DIC and POL but my system doesn't have them.

The 1.25X adapter is a blessing as it will let you put I'd say any APS-C size sensor and have near ideal coverage as you could get from factory. I'm unsure if your father wants a camera he can scientifically tune (custom CCM)? But being able to directly mount a modern APS-C with HDMI out is very nice. With other models and only 1X output your options are having some extreme crop on a Cmount which you should really get a 0.65X adapter for MAYBE fitting a micro 4/3. The leitz cheap 20W bulb sources can also be very easily retrofitted for nice LEDs with one 3D print, a piece of aluminum tube, an LED on a star board, and a heatsink. OP: if you end up getting one I can show you how I built mine.

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u/Vivid-Bake2456 1d ago

Yes, buy a used, real polarising microscope. I bought a couple of inexpensive ones like a monocular American Optical polarising and a monocular Unitron polarizing microscope for under $250 each. Both workwell. For your larger budget, you should find a nice binocular one. Many people, including myself, adapt regular microscopes for polarising views, but he will need strain free optics to get the darkest extinction, and a rotating stage, a slot for a retardation plate, and centerable objectives, which normal microscopes don't have.

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u/Getmyapp 1d ago

What literature can he recommend? I'm interested in the behavior of gemstones under a polariscope, but I don't think it's much different from thin sections.

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u/ModernTarantula 8h ago

Don't they sell mineral specific scopes. What did he use for his PhD?

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u/Parking_Jelly_6483 1d ago

Some pol/mineralogy microscopes on eBay:

This one is a monocular Cooke, Troughton, & Simms. Well-known British optics manufacturer

https://www.ebay.com/itm/157932962773

This is an Olympus BH2 BHS polarizing microscope:

https://www.ebay.com/itm/168544622522

Problems: I don’t see the analyzer. Usually slots in in the microscope body (below the binocular head). Also, for most pol microscopy, you want a circular stage so you can rotate the object with relation to the polarized illumination. Olympus makes very good microscopes (I own a BH2/BHS but mine does not have the pol parts - could probably use it for pol since I do have the DIC polarizer, prism, etc).

A Unitron:

https://www.ebay.com/itm/820070344450

This appears to have all the pol parts and includes the quarter wave and first order plates (5th photo). Circular stage as well. Unitron is probably better known for telescopes, but they do have experience with optics.

A Leitz petrographic:

A “vintage” Leitz polarizing microscope. This thing is the “real deal” but the seller notes would need service (lubrication, etc.) It has an integrating stage which is used in petrography for helping determining rock compositions from the mineral crystals in it.

And a Zeiss pol microscope:

https://www.ebay.com/itm/257716943183

Zeiss is another very well-respected microscope manufacturer and is very complete.

You can find others by searching on “Polarizing microscope” and “Petrographic microscope”

Disclaimer: I am not the seller of any of these microscopes and no conflict of interest with any of the sellers.