I just purchased a 90mm elmarit with a marking on the side of the lens head. Not only is the last 3 digits of the serial number there but it also has a # 37 and then about an inch around the barrel are two zeros. Ant idea what these two zeros mean? Thanks

-- carlton phelps (leicadaddy@cs.com), December 25, 2001

Answers

These are, I believe, a notation of the exact measured focal length-- or the deviation from the nominal FL. My 90 Elmarit says, 44, with 00 underneath the 44. These are hand-scratched into the barrel. My guess is that your lens measures 93.7mm, and mine is 94.4.

I don't completely have the hang of these markings yet, though. If that's not right, John Collier will fill us in soon!

I don't know what the "00" is for.

John? Somebody?

-- Bob Fleischman (RFXMAIL@prodigy.net), December 25, 2001.

Go to this site to find out about those funny numbers on your lens

-- Al Smith (smith58@msn.com), December 25, 2001.

Regarding that linked site from my post above... be patent and let it fully load...it will go right to the correct section of that dense site. It just takes a couple of seconds.

-- Al Smith (smith58@msn.com), December 25, 2001.

Carlton, my 90 Elmarit has "90" engraved on the focusing mount near the infinity mark, to the right of the "m" (for meters). See if yours does, too. If it does, then it looks like the "00" mark means that there's no deviation from the nominal FL. In which case, I don't know what the #37 means.

-- Bob Fleischman (RFXMAIL@prodigy.net), December 25, 2001.

This is a repeat of my wording on the old site

http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=005c Tt

The German word for these small number engravings means "focal length groupings". They appear exclusively on M 50, 90 and 135 mm lenses and serve as a better identification of exact production data for each lens manufacturing. As they would say (again in German), for example, "50 doesn't always mean 50". All numbers yield the same optical quality! Actually these numberings are only at home for customer service application. Examples are:

on 50 mm: 00 = 50.0 mm, 10 = 51.0 mm, 11 = 51.1 mm, 16 = 51.6 mm, 22 = 52.2 mm.

on 90 mm: 95 = 89.5 mm, 00 = 90.0 mm, 05 = 90.5 mm, 10 = 91.0 mm.

on 135 mm: 45 = 134.5 mm, 50 = 135.0 mm, 55 = 135.5 mm, 60 = 136.0 mm.

-- Michael Kastner (kastner@zedat.fu-berlin.de), December 26, 2001.

Thanks, Michael. So, then what does the "44" mean where it's hand- scratched into the anodising of my 90 Elmarit. It reads 44 over 00. And what does the "37" mean on Carlton's 90?

BTW, apparently they didn't always adhere to this system. My DR Summicron is simply marked, on the lens head, "51.9." I assume that's the true F.L.

-- Bob Fleischman (RFXMAIL@prodigy.net), December 26, 2001.

Bob,

As to your "44" and "37" I don't immediately know what's up. Remember that some numbers are to be added to the *.0 mm, while others are to be subtracted therefrom! The numbers I showed you were those I got as an answer from Solms, so that I don't know what their limitations are, i.e. what the "scopes" are... e.g. whether everything here is in 0.1 mm or 0.5 mm packs or indeed in any old digits. Other than that, the "scratching" may mean simply that a non-uniform numbering has been incorporated subsequently.

But I'm working on it. 'Ave ze nice New Year. Mike

-- Michael Kastner (kastner@zedat.fu-berlin.de), December 27, 2001.