Monochromatic Microscopes?

[mneium]

After reading about monochromatic photomicrography and its benefits, I wondered why there don't seem to be any microscopes designed from the ground up for monochromatic usage?
If you only have to make a flat field for one single wavelength, and you don't need to worry about chromatic aberration at all, can't you make vastly better (wider & flatter field) objectives for vastly less money?

[Pau]

Well, any microscope is monochromatic if you use monochromatic light.

A green filter has been a standard accesory with most new microscopes for long time for the very same reason you suggest

[mneium]

Hm, but I mean a microscope where all of the corrective elements are designed for monochromatic light (allowing much better field size & flatness at a given level of manufacturing effort.)
I guess on an infinity-corrected microscope, only the objectives would need to be monochromatic, since corrections only occur in the objectives.

[René]

since corrections only occur in the objectives.

Eh, no, the condenser plays a part too. Anyway, who's the buyer for whom you claim this benefit? The professional market has no problem with the price of the supercorrected optics available nowadays. I don't see any interest from the amateur side for B/W microscopy, especially not with the cheap chinese objectives available nowadays with great value for money. Mass production is key, of course.
But to get back to your initial question: of course there is a specific market for monochromatic optics, especially in industry. Considering biology, UV transmission microscopy with quartz objectives has roots back to the early 1900's. Getting things in focus in the old times was a difficult process, as it was way off from that using visible light. Modern objectives do that nowadays splendidly (at a price!). And for the IR region there are also specialized mirror objectives with the advantage of no intrinsic chromatic abberation.

Best wishes, René

[PeteM]

One might argue that a SEM is a microscope designed from the ground up to be monochromatic . . . and achieves incredible resolution as a result. So, it's been done, sort of.

As for light microscopes in the visual range, while there's a slight gain in resolution, the loss of color is a pretty big deal. For beginners (where less cost really counts) it's sort of like buying a B&W television -- who wants that when color is available for a tiny bit more?

At the advanced hobbyist and professional level, the loss of color eliminates much of the information gained both in normal viewing and with various stains and fluorochromes. And as Pau noted, in the cases that extra bit of resolution was needed, a green filter helped. These days, microscopes (laser scanning etc.) have moved beyond that for higher end work.

[Lou Jost]

Actually there are microscopes designed to be monochromatic from the ground up. They are called comparators or profile projectors and both Nikon and Mitutoyo make objectives for them.

https://www.ebay.com/itm/Nikon-Comparat ... SwBRVaaqbP

https://www.ebay.com/itm/12-Nikon-V12-O ... SwCA5baeV2

https://www.ebay.com/itm/Nikon-comparat ... Swu-tem4og

These use mostly monochromatic illuminators to get sharp edges that are not blurred by CA. I have some objectives from these. The objectives are interesting for their pellicle epi-illumination and for their price. They are very cheap. But they don't have high NA.

[Lou Jost]

There are also economical, extremely good 5x and 10x monochromatic "objectives" with high NA (greater than 0.35 in many cases), zero distortion, perfectly flat fields, and enormous image circles. These are among the best optics in existence, as long as you use the right wavelength of light. They are the microphotolithography lenses used to make electronic chips. When they were new they cost hundreds of thousands of dollars in some cases, but now they can be bought on eBay for a few hundred dollars. Some of them work in the ultraviolet, giving extra resolution compared to visible light objectives. They unfortunately have poor working distances, though if you can use transmitted light, this is no problem.

[Macro_Cosmos]

I've tried some of those objectives, and a friend owns a bunch of them. Some are unwieldy beasts, extremely heavy and mounting is far from trivial. I tried out a 5x Zeiss something, it was huge, threadless, shaped like a fat bowling pin. My friend uses some sort of collar to mount them. Definitely a fun project if one has both the time and passion.

[Lou Jost]

They come in all sizes, from smaller than a Nikon 105mm macro lens to room-sized. They are by far the highest quality lenses that ordinary humans can afford. I use them, and the small ones are not hard to work with except for the lighting problem. Some of my bigger ones require 600mm between the object and sensor, and this does cause problems, but they are not insurmountable.

[Pau]

There are also economical, extremely good 5x and 10x monochromatic "objectives" with high NA (greater than 0.35 in many cases), zero distortion, perfectly flat fields, and enormous image circles. These are among the best optics in existence, as long as you use the right wavelength of light. They are the microphotolithography lenses used to make electronic chips. When they were new they cost hundreds of thousands of dollars in some cases, but now they can be bought on eBay for a few hundred dollars. Some of them work in the ultraviolet, giving extra resolution compared to visible light objectives. They unfortunately have poor working distances, though if you can use transmitted light, this is no problem.

Despite being able to be used for microscope magnification and resolution imaging, these lenses hardly can be called microscope objectives. AFAIK they are designed to work inversely, projecting a very high resolution reduced image of a photomask. Very interesting stuff in any case.

[Lou Jost]

Yes, that's why I put the word "objective" in quotes. They do act as objectives when reversed. They are amazing lenses, with no rivals in terms of lack of distortion and flatness of field and image circle size. And they are relatively cheap.

[mneium]

There are also economical, extremely good 5x and 10x monochromatic "objectives" with high NA (greater than 0.35 in many cases), zero distortion, perfectly flat fields, and enormous image circles. These are among the best optics in existence, as long as you use the right wavelength of light. They are the microphotolithography lenses used to make electronic chips. When they were new they cost hundreds of thousands of dollars in some cases, but now they can be bought on eBay for a few hundred dollars. Some of them work in the ultraviolet, giving extra resolution compared to visible light objectives. They unfortunately have poor working distances, though if you can use transmitted light, this is no problem.

Wow, sounds amazing. What kind of names are these things identified under?

[Lou Jost]

On ebay they are often labeled "photolithography lenses". The most common ones are made by Zeiss.

As people have said, these are not simple to use and they can only be used at or close to the rated wavelength (usually 546nm, 436nm or 405nm). These lenses incorporated the absolute best technology of the time, sparing no expense; cost was no limit.

[Lou Jost]

Here's a rare ultraviolet one, which would be useful to UV photographers

https://www.ebay.com/itm/Carl-Zeiss-365 ... Sw0kpf90-f

Weighs 20 pounds!!!!!

[chris_ma]

there are some cool looking ones out there. like this one:
https://www.ebay.com/itm/Giant-Photolit ... Sw0w5eXuh4

also love the description:
"Optical properties: really really big"
at 38" x 20" x 10" they weren't kidding

the zeiss website also has a cool looking one:


I suspect that weights and costs a bit more