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Does anyone know who the manufacturer of this condenser was?

Thanks for the help

Let's see if it helps!!!
Full text:

At the top:

"für Objektive 9 1/16"


On the barrel:

"für Objektive 6 - 8"

"für Objektive 3 - 5"

"Kl.Proj.-Zeich.App."

The way I have typically branded condensers is stylistically. Comparing lettering, knurling and lathing and if available the design of the iris handle. None of that checks any boxes for me plus there were a considerable number of German makers. I have to assume it is German. Interesting stacked design.
I have some odd items from some lesser known to obscure makers, Schutz, Weddig, Voigtländer, C B S, Hacker, Seibert. I will check the font on those items and see if there is any similarity. That's a start anyway.

Apocronaut, thanks again.

I'm helping a lady friend whose husband worked for Jena many "centuries" ago. He passed away 2 years ago and now has a huge collection (130 lenses, many of them Carl Zeiss Jena) of objects they want to classify.

I have the privilege of doing so, but my knowledge, compared to yours, is zero.

She needs that help.

Greetings

Esteban

P.D. (Part of it)

So then, might that not be pre-war Zeiss or possibly ROW? Weddig was in what became East Germany too.

Apochronaut, look what I found. Looks very similar, maybe the brand is Leitz. (I made similar pictures for you but the piece at the back is not a Leitz)

Well this lister thinks this is a dark field condenser and says it also might be a Leica? So maybe they don't have.it labeled oll korrect.

Leica was not a microscope company until the 1991 merger. This condenser easily could be Leitz but not Leica. It is not a DF condenser.. It is a stacked BF condenser with sectional N.A. increases matching that required by the grouped objectives coupled to it's matched system. A DF condenser has to have a central obstruction or field stop to block the direct rays. This condenser does not have that feature.

BramHuntingNematodes wrote: ↑

Wed Apr 10, 2024 10:26 pm

Well this lister thinks this is a dark field condenser and says it also might be a Leica? So maybe they don't have.it labeled oll korrect.

You are right!

apochronaut wrote: ↑

Thu Apr 11, 2024 2:59 am

Leica was not a microscope company until the 1991 merger. This condenser easily could be Leitz but not Leica. It is not a DF condenser.. It is a stacked BF condenser with sectional N.A. increases matching that required by the grouped objectives coupled to it's matched system. A DF condenser has to have a central obstruction or field stop to block the direct rays. This condenser does not have that feature.

Maybe it comes from here and got confused because of title title: "Darkfield Accessories": But this leads me to another question, in the condenser that I have it talks about objectives 6 -8, 9 1-1/16, 3-5 which I assume was used at the beginning of the 20th century but not in 1951 which does not have any text but It looks the same as the one I have.


Were they reusing old stock?

It was pretty hard to improve on a 1.40 achromat aplanat and most companies didn't need to because their objective range seldom exceeded a 1.40. Winkel made a 1.52 condenser in the 50's/60's. Leitz probably made that or a very similar condenser for 40 years, eventually marking the an N.A. on it.
Leitz seemed a traditional company too, clinging to numbered objectives long after most others and refraining from using N.A. markings, although that information was probably in a catalogue. They started double marking the magnification potential on them in the 30's likely..
Some old instructional lextbooks referred to objectives by number and microscopists who trained up to a certain point in time in continental Europe knew implicitly what a #4 objective was for instance. Elsewhere, the focal length was the important spec. Oddly, some European companies measured focal lengths in inches long after the practice was abandoned in the U.K. and U.S. In the 1890's, Spencer offered objectives as short as 1/30" but after about 1905 the shortest was 1.5mm.

So it could be this condenser from the 20s to the 30s, right?

Guessing but seems so. It is probably a very good condenser for higher N.A. objectives but it was for a microscope that utilized a mirror and remote illuminator, so it has a longer front focal length. It would work better on a microscope with a rear mounted illuminator, collimating optics , field diaphragm : a classic Köhler set up, than it would on a shorter bodied scope with an under stage illuminator.

Apochronaut, thank you again for your great help.

Regards

Steve from Madrid

Hope it all works out for you. I use a somewhat similar condenser on a B & L Balplan Research stand. The chief engineer of the Balplan made a 125X 1.40 Flat Field Apochromat prototype and he and a colleague patented a really nice compatible condenser to go with it but I have never seen an example of the condenser, just that I have the objective. The commonly available 1.25 abbe aplanat for that microscope works pretty good but I adapted an older 1.40 achromat/aplanat that was made by B & L for decades up until about 1960 for horsehoe research stands fitted with apochromats. Seems to do the job, maybe a little better. Both need oil to service that objective properly.

I don’t wish to hi-jack this fascinating thread, but I thought this recently acquired low-power condenser might be of interest:
. .
MichaelG.
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Edit: __ I have been racking my brains to think of a German lens designated 3cm … and the only one I have found so far is the Tessar, from Zeiss Jena, that was fitted to the Robot camera. … Any alternative suggestions would be most welcome !
Update __ Just discovered that there was also a Mikrotar [which might explain the M
https://www.ebay.ph/itm/166141854601

I believe that I have solved my little mystery
… here is a family member !

https://www.mikroskop-online.de/mikrosk ... otar-45cm/

MichaelG.