MicrobeHunter.com Microscopy Forum

Is it possible to determine the time or year in which these lenses were manufactured by E.Leitz?
Thanks for the help

Is the 6 not just a partial? Leitz shorter focal length objectives could be separated, so that a funnel stop section or iris diaphragm section could be threaded into the lens section.
Likely 1920's based on the knurling and brass. Chrome plating wasn't used prior to the early 20's. Lacquered brass was the defacto finish until chrome became a better option. It took a while for chrome to be adopted though. By the early 30's chrome was becoming common but some companies used chrome on the lower section prior to adopting an all chromed objective. Nickel was also used on the lower section, usually on objectives that were unlikely to be in contact with anything corrosive. Note the inversion of the Leitz logo. That probably took place at a specific time. If you can find some old catalogues on line, that might indicate a date for that. I think the #6 might be slightly older.
The numbering scheme went from 1 to 9, later replaced by a magnification ratio, 24 : 1 for instance. A # 3 objective was later marked 10:1. A # 4 was 24: 1, # 5 approx. 45 : 1, # 6, 54: 1, # 7, 63: 1 I have the exact same objectives as your #3 and 6 but they are all chrome. One is marked both 3 and 10: 1 on the other side.

Is the 6 not just a partial?

Yes, it is empty. Again thank you apochronaut for your precious help.


Thanks to the clues you have given me, I believe that the lens was possibly sold from the year 1914 onwards.
On eBay there is one with the serial number 169234 from the year 1916 with the lens No. 3 very similar to my one
with the detail that the brand is not only engraved on the barrel in written form as it was in 1900...
...but already bears the famous E.Leitz logo (although in this case the number 3 and the logo are turned upside down).

Chromium plating for commercial use was exclusive to the U.S. until after 1925. Although some small parts were plated in the early 20's, they didn't start using chrome for things like automobile bumpers until around 1927. I have a brand new # 7 objective of that same form as your 6, identical to the #7 in the picture actuslly but it's tip is lacquered brass. Earlier plated ones would have been nickel likely. I have seen some other metals plated on the tip in ealier objectives by other makers.
Check and see what the plating is. Nickel would almost surely be tarnished some by now and even when bright it is noticeably greyer than chrome.
From the picture you posted , yours looks to be nickel plate, so your date is probably not far off.

Apochronaut I think you are the one who can best judge this subject with the images I am publishing now.

Thank you for your time.

Another thing I've noticed between the 3 and 6 is the way the head threads onto the barrel.

I would say not chromium and probably a nickel alloy. Some version of what was at the time called German Silver. Copper, nickel and zinc in varying percentages ,, depending on who made it and what it was made for. It was widely alloyed in Germany after about 1870 or so., used frequently where a bright finish, hardness and some corrosion resistance were needed. It was the stainless steel of it's day being used in solid form or as plate for cutlery.