Would someone educate this ptifully ignorant old man? Does the orignal version of the 50mm Elmar 2.8 have a focusing tab, or does that knob on the side of the barrel serve another purpose? I've been considering the old version of this lens because I thought it had a focusing tab. Someone help me out here. Thanks, Dennis

-- Dennis Couvillion (couvilaw@aol.com), November 26, 2001

Answers

Dennis:

I'm no expert, and am trying to learn about this lens myself. The ones I've seen have that tab. As far as I can tell, the tab serves two fucntions: One as a focus tab; two, the earlier lenses locked at infinity, and the little button on the tab releases that lock. The infinity lock is nice as it aids in preventing lens twist while locking the lens in the extended position.

-- Jack Flesher (jbflesher@msn.com), November 26, 2001.

Yes the original one (57-74) does have a focusing tab. The new recomputed one does not.

-- John Collier (jbcollier@powersurfr.com), November 26, 2001.

Dennis, The tab (button) serves two functions on the original 50 Elmars--3.5 and 2.8--as a focussing tab (without it, it is impossible to turn the focussing ring) and as an infinity lock. Without the tab locked at infinity, it is very difficult to both mount and remove the lens. The newer lens has the tab and serves only as a focussing tab--although one could focus the lens without it.

-- Henry Chu (heninden@yahoo.com), November 26, 2001.

Is it possible there are two versions of the current model? The one I tested a few weeks ago in New York did NOT have a focusing tab. However, I believe I saw a picture of one on an M6J with a focusing tab. Could it be that the one that came on the M6J differs from later production models?

-- Dennis Couvillion (couvilaw@aol.com), November 26, 2001.

Dennis, let me have a go at this. The original collapsible summicron, as well as its rigid equivalent, had a focus tab. The second version, the dual-range Summicron, does not. The one which followed it, the third version, offered from 1969 to 1979, has not got one, either. The next time the lens was recomputed, it was given a focus tab. The difference between that one, and the original one from back in the fifties, is that in the more recent version the tab is ONLY a tab--and not a button that you had to depress to release the infinity catch.

Now (actually, this may be what you are referring to): the current lens is the same optically as its recent tabbed predecessor, only without the tab. So from that point of view you are correct: there are two optically identical versions of the same lens. It's just that they are not both current, in that the tabbed version is no longer made.

Hope that clears it up.

Regards,

-- Bob Fleischman (RFXMAIL@prodigy.net), November 27, 2001.

Dennis, when I saw your later post, I realized you said Elmar, not Summicron. SO I told you all about what you didn't ask. Oops. I had both the 3.5 and 2.8 Elmar, and they both had a focusing tab.

-- Bob Fleischman (RFXMAIL@prodigy.net), November 27, 2001.