MicrobeHunter.com Microscopy Forum

Hello,
I started collecting antique microscopes recently and just found this interesting forum. I hope I can contribute to interesting discussions, and I am also trying to find some answers about one of my most recent acquisitions. I am a microbiology lecturer in the UK, and I usually work with most advanced microscope technologies. But I am really interested in antique microscopes!
So I found a nice microscope for which I could not assign yet a maker (some photos are shown in PDF attached). There are no words or numbers engraved on the microscope (including the base). I found no identical microscope during my searches, but the type of base suggest it should have a British origin. I think this should be form c. 1900.
It came with one objective from Ernst Leitz Wetzlar (1/12 Oel Immersion), two unsigned objectives (2/3 and 1/6 inch).
What is really puzzling is the fourth objective (which is pictures in the photos attached). This one contains the following inscriptions:
Carl Zeiss Jena D. R. P. 84996
Planar 145 f = 3.5 mm D. R. P. 92313
Serie I a, Nº 2 Nº 25286

This objective/lens contains an inbuilt iris diaphragm, and D.R.P. means German patents that where issued to Carl Zeiss in 1894 - 1897. After contacting the Carl Zeiss archive, they don't know much about this lens or its use, but the serial number dates the lens too c. 1900.

I have no idea about the use of this kind of lens in this microscope. Maybe for photomicrography?
No idea...
Please let me know if you have some hint about this lens and the microscope.
Many thanks,
Joao

Welcome Joao

I can help just a little with Patent 92313 [*]

See here:
https://www.reduser.net/forum/showthrea ... -evolution
but unfortunately Espacenet doesn't appear to have a copy of the German patent on file.

... They do however have the US version:
https://worldwide.espacenet.com/publica ... cale=en_EP

MichaelG.

[*] Zeiss should really know this stuff !
.

P.S. according to this page:
https://docplayer.net/22641054-Anastigm ... gmats.html
at paragraph 8

DRP 84,996 This covered a compact focusing mount and iris diaphragm.

Carbon arc was the illumination source for microscope photos in 1900. Even when high output tungsten filament or tungsten ribbon filaments arrived having an iris diaphragm in the objective lens for exposure control and some depth of field adjustment, was necessary because the illumination systems themselves were not regulated. Later, Zeiss patented the Tessar and it became a popular lens for microphotographs.

Thanks MichaelG and apochronaut,
I have the German patents sent by the someone very nice from the Carl Zeiss archive. And they tried to help with this query, and other queries I sent them before. But unfortunately, they don't have more information about this lens. They suggested it may be what they called a 'mikroplanar' for microphotografic or microprojection purposes (http://www.archive.zeiss.de/zeig_start. ... &zeig=3814).

I have have no clear idea how people did photomicrographs in the old times. So, thanks apochronaut for the information. I will try to search about this topic.
Cheers

Sounds to me as if it is an anastigmat lens, designed for photography, hence the iris. More modern (but still 1970s onwards) equivalents are the Zeiss Luminar and Leitz Photar range. They form a real image, without an eyepiece and give magnification ranges from x1 to x 20 isn, depending on focal length of course.

Leitz produced ones called Summar and Milar in the 1960s, and Nikon called theirs Macro-Nikkors (whereas their camera 'macro' lenses were called Micro-Nikkors !). Olympus had the 20 and 38mm versions (later with OM mounts rather than RMS) and Polaroid supplied a range of lenses for their MP-4 stand, which I think were actually made by Tominon.

Brian Bracegirdle discussed many of these in some of his books, such as 'Scientific Photomacrography' and the later 'A History of photography with the light microscope'.

Using an adapter, it would easily connect to bellows and give you high mag macro.

JIS wrote:Thanks MichaelG and apochronaut,
I have the German patents sent by the someone very nice from the Carl Zeiss archive.

That's good to know ...
I have sent you a personal message

MichaelG.