Odd Leitz UV objective - any Leitz historical experts?

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jmc
Posts: 96
Joined: Fri Apr 17, 2020 3:14 am

Odd Leitz UV objective - any Leitz historical experts?

Post by jmc »

Some historical advice needed please.

I recently bought a Leitz 16x UV objective It's marked up as 16 / 0.25 and 160/0.35 Q. Picture of the lens below;

Image

On the other side of the lens it says "Leitz Wetzlar Germany 620683".

It's got an RMS thread.

I've measured the lens transmission through this, and it looks good down at 280nm which is as far as I can go, so it is definitely an unusual objective with quartz and/or calcium fluoride rather than glass elements.

I was wondering if anyone with Leitz historical knowledge knew anything about it, and when it was from? I've been able to find nothing online, apart from a reference to a Leitz UV microscope used for looking at wood in a paper dating 1967, but I'm not even sure if this was from that.
Jonathan Crowther

Rorschach
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Location: Finland

Post by Rorschach »

Since this is 160mm tube length, doesn't that preclude the possibility of being designed for the system mentioned in the paper you found?

I may be wrong but I was under the impression that Leitz scopes of the 60ies were all 170mm (or, in the case of metallurgical scopes, infinity)?

Back in the day, it usually took a year or two, if not more, for data to get written into a manuscript and for that to then get accepted in peer review and published. So most likely the actual scope work for that paper was done in 1966 or 1965, possibly even a bit earlier.

jmc
Posts: 96
Joined: Fri Apr 17, 2020 3:14 am

Post by jmc »

No idea Rorschach, I still have a lot to learn about these systems and their history.

Just been doing some more digging, and apparently the Laborlux-12 was 160mm tube length, and the pictures I've seen of the objectives look very similar. This is much newer than I originally thought, and looks to be 1980's era. Perhaps there was a Laborlux-UV?
Jonathan Crowther

Pau
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Post by Pau »

This is for sure from a special instrument working with short UV
160/0.35 Q 0.35mm quartz glass is not at all a standard microscope slide! (160 DIN tube length is typical of the later finite Leitz microscope series, most my objectives are Leitz 160, nothing unusual here)
Pau

jmc
Posts: 96
Joined: Fri Apr 17, 2020 3:14 am

Post by jmc »

Thanks Pau. I've contacted Leica to see if they know anything about it from their records, although I'm not sure whether that'll get me anywhere. I've had good dealings with Zeiss in the past trying to find out about a lens, so 'fingers crossed'.

Here's the scan of the transmission spectra I ran in the UV.

Image

It gets a bit noisy down at 280nm with my setup, and I reckon absolute transmission is a bit higher, as the small objective diameter makes it hard to measure without clipping the edge of the light beam. Even so it's showing no signs of dropping off quickly by 280nm, so I'm assuming this would still be good down at 250nm and perhaps even lower.
Jonathan Crowther

Ichthyophthirius
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Post by Ichthyophthirius »

Hi,

I suspect (but have no prove) that they are the answer to Zeiss' Ultrafluar objectives. Ultrafluars are 230 nm - 700 nm achromatic objectives also used with 0.35 mm Quartz cover slips.

Zeiss Ultrafluar 32/0.40 still has approx. 50 % transmission at 240 nm!

Regards, Ichty

jmc
Posts: 96
Joined: Fri Apr 17, 2020 3:14 am

Post by jmc »

Quick update. I've managed to get a couple of other Leitz UV lenses from a shop in Germany (Optik Online). Thanks to Ichty for posting the link to that.

Here they are. Leitz UV 40x / 0.65, glycerin immersion.
Image

And the Leitz UV 100x / 1.20, glycerin immersion.
Image

Both show the good transmission down to 280nm using my measurement setup that I saw for the 16x version.

As an aside (and a need to rant slightly), oh my lord, how expensive are quartz slides and coverslips!!!!
Jonathan Crowther

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