Rangefinder coupled lenses without SN numbes

[nitroplait]

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I was originally under the impression that un-numbered rangefinder coupled lenses would be 5cm Elmar lenses originate from Leica IA cameras and converted to standardised cameras with or without RF coupling.
Like the one on my IA converted to IID:

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That seem not to be the case.

(all data below from our Leica Wiki)

The first standardised Leica camera was introduced in 1930 (Leica IC) - but it did not have rangefinder coupling.
The first Leica with rangefinder coupling was the IID, which was introduced in 1932.

Yet, I notice there are coupled lenses from long before 1932.

For example; the fat Elmar 90/4 was coupled already from 1930 it seems.

And fuelling this question: I recently I got a nickel Elmar 3.5cm f/3.5 seemingly without SN number, which I would assume indicating it is one of the earliest 3.5cm lenses manufactured, before the Wiki start of the serial number range beginning at 935 (1930), yet mine is RF coupled (heavy cam).

The lens in question on the right hand. 

 

If my assumptions above are correct, then why would a RF coupled lens exist 2 years before RF cameras existed and why would it not have a serial number?

Any ideas?

[jerzy]

good questions... some of early II that I have seen had 11 oclock Elmar 5cm (without infinity lock) with no serial number visible oustside, few of them had serial number inside. (but there is no 100% proof that these lenses belonged to camera initially). First II left the factory in November 1931 (see some positing from Giuliobogazzi), possibly pre-production. First step with rangefinder coupled lenses was to define parametrs for rangfinder (relation between deflection of arm and distance - and this is different than in Fodis). But this must have been definded earlier than November 1931. So in theory it is possible that copupled lenses could have been produced as early as first half of 1931. However I would assume that these would have been standard, 5cm Elmars. But who knows.
Your lens could be such, or it could have been converted from non coupled end of 31/ beg 32.

[willeica]

5 hours ago, jerzy said:

it could have been converted from non coupled end of 31/ beg 32.

I suspect this was the case most of the time. I have a number of lenses without SNs which are coupled. They also were converted to 7 O'Clock in some cases. As we noted before, Jerzy, some of them have quite short lens barrels. Also, any lens taken from a I Model A is in a 33mm mount and would have to be converted to a 39mm mount to fit on any camera from the I Model C onwards. Leitz had the facilities and skills available to do all kinds of modifications to its lenses.

William