Leitz Infinity lock: "11 o'clock vs. 7 o'clock"

[Luddite Frank]

When did Leitz change-over from the the so-called "11 o'clock" Infinity lock to the "7 o'clock" Infinity lock ?

Where there any lenses beside the Elmar 50 /3,5 that used the 11 o'clock lock ?

Thanks - sorry if this has gone 'round before' !

Luddite Frank

( I have a nickel Elmar, s/n 99xxx, with 11 o'clock lock )

 

[Luddite Frank]

Round-about answer to the 7 come 11 focus lock question...

Round-about answer to the 7 come 11 focus lock question...

I accidentally found a partial answer to my own question: "When did Leitz abandon the 7 o'clock Infinity lock in favor of the 7 o'clock version.

Today, I was out shooting at Steamtown National Historic Site, in Scranton, PA, with a shutterbug friend.

I had one Barnack loaded with 800 Fujicolor, shooting a Canon f1.8/ 35 lens. The other camera was a black Leica III, loaded with Ilford 3200 B&W, with an f 2 / 50 mm Summicron: we started indoors in the Roundhouse (very dark).

When we moved outdoors from the roundhouse, I decided to put the 3200 camera away. I swapped the Summicron to the camera with the 800 ASA, and wanted to drop the 35mm lens in my shoulder bag. I thought I'd stick my 1932 nickel Elmar 50 ( 11 o'clock lock) on the black III, just to keep the body sealed-up.

I quickly discovered that the 11 o'clock Infinity lock will not clear the slow-speeds dial on a Leica III.

Unless someone says otherwise, I will presume that Leica brought out the "7 o'clock " Infinity lock around 1933, to go with the new model III cameras...

And I guess I'll put my nickel Elmar back on my black Leica II (1932)...


LF

 

[Rob-F]

Well, Frank, I am satisfied that you have solved the mystery. Your theory is too right to be wrong, as it is supported by empirical evidence!

In my mind, the greater mystery is why they ever put it at 11 O'clock in the first place. It is certainly not handy there! Any Ideas on that?

 

[Luddite Frank]

There is a picture "Evolution of the Leica", ( page 4 of 1953 edition of the Leica Manual), which shows from front to back: Oskar Barnack's UR Leica of 1914, the Leica "Null" of 1924, and the latest, a 1952 III-f.

Both the 1914 and 1924 versions have the 11 o'clock lock.

My guess is, it was good enough for Oskar Barnack, and it did not become a hindrance until the slow speeds were added with the Leica F (III) in 1933...

I would love to know at what point the staff at Ernst Leitz figured-out that the
11 o'clock lenses would not work with their newest model... did they catch this in the design-stage, or not until someone tried to screw a lens onto the first F prototype... ?

"Necessity is a mother"...

So were there any other 11 o'clock LTM lenses - Summars ? Hektor 50 ? Elmar 35 ?

LF

 

[dlove5]

Lager's Leica Illustrated Guide II mentions the Hektor 50 and Elmar 35 also started as 11 o'clock LTM lenses. He mentions this changed in late 1932 or early 1933. The Summar started in 1933 and is not mentioned as being an 11 o'clock lens initially.

 

[john neal]

Frank,

What David said above - somewhere in the 1932 - 33 range they dropped the 11 0'clock tab.

Incidentally, if you set your Elmar to its close focus setting it should clear the slow speed knob as you mount it, but only just!