batterytypehah!
Lord of the Dings
Allows moving your aperture ring with one finger, and places the dang aperture scale where you can see it in the first place. Focussing down from inf. comes afterwards.
That's right, I don't do "F.A.S.T." Never did like it. Light changes less often than distance.
That's right, I don't do "F.A.S.T." Never did like it. Light changes less often than distance.
David Hughes
David Hughes
Well, I've been using them since the 70's, have a dozen or more and have read this thread through twice but I'm still none the wiser.
Attempts to stop the "big bang" seems the nearest we'll get to the truth. But probably not as we know it...
Regards, David
Attempts to stop the "big bang" seems the nearest we'll get to the truth. But probably not as we know it...
Regards, David
David.Boettcher
Established
Hi David,
Yes; I was convinced that I was just missing something obvious, but it seems no one knows why the infinity lock is there - at least no one in this thread so far. Maybe it was not such a dumb question after all . . .
Regards - David
1ScrewLoose
Member
I think there might be something to the hyperfocal business, but in the other direction. I only have one lens with an infinity lock (rigid 50mm cron) but the infinity lock is positioned so that one "bumps against it" exactly at the hyperfocal distance for f8... is that the situation for other lenses so endowed?
David.Boettcher
Established
I don't think so. I just checked a 5cm Elmar and a 5cm Summar and the focussing lever bumps into the start of the infinity stop at the f4.5 hyperfocal distance on the Summar, and just over f4.5 on the Elmar. Not really an ideal setting for hyperfocal, unless I suppose you were working with very slow film.
Regards - David
David Hughes
David Hughes
Hi,
I've a reasonable collection of Leica literature from the 1930's and the infinity lock is often mentioned but never explained.
F'instance: in "Handle the Leica" (August 1938, London) it says "This lever ensures rapid and steady focusing of the lens" but nothing else.
In "Leica the camera of modern times" (April 1937, Wetzlar & London) it says nothing about it at all.
And in "The interchangeable Leica lenses" (October 1937, Wetzlar) it says "When the focusing mount reaches the 'infinity' mark, it locks in position ...". It adds that only the 2.8, 3.5 and 5cm lenses have them.
And that seems to be it; I've the "Summar" and "Summitar" leaflets and they say nothing (from memory, as I can't find the "Summar" one). There's nothing in the little lens tables book and the 3 part "Directions" is also vague.
I'd high hopes when I opened the "Supplementary Directions for the Standard Leica Camera" (January 1934, Wetzlar) as there is a page headed "Focusing the infinity near point" but it's about the hyper-focal distance and refers you to the little lens tables book.
Sometime this evening I'll try and plough my way through the unofficial "The Leica Data Book" by Karl Barledon (Ohio 1934) and, of course, Morgan & Lester's, Kisselbach's and Matheson's books but I have my doubts even now.
Regards, David
I've a reasonable collection of Leica literature from the 1930's and the infinity lock is often mentioned but never explained.
F'instance: in "Handle the Leica" (August 1938, London) it says "This lever ensures rapid and steady focusing of the lens" but nothing else.
In "Leica the camera of modern times" (April 1937, Wetzlar & London) it says nothing about it at all.
And in "The interchangeable Leica lenses" (October 1937, Wetzlar) it says "When the focusing mount reaches the 'infinity' mark, it locks in position ...". It adds that only the 2.8, 3.5 and 5cm lenses have them.
And that seems to be it; I've the "Summar" and "Summitar" leaflets and they say nothing (from memory, as I can't find the "Summar" one). There's nothing in the little lens tables book and the 3 part "Directions" is also vague.
I'd high hopes when I opened the "Supplementary Directions for the Standard Leica Camera" (January 1934, Wetzlar) as there is a page headed "Focusing the infinity near point" but it's about the hyper-focal distance and refers you to the little lens tables book.
Sometime this evening I'll try and plough my way through the unofficial "The Leica Data Book" by Karl Barledon (Ohio 1934) and, of course, Morgan & Lester's, Kisselbach's and Matheson's books but I have my doubts even now.
Regards, David
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dave lackey
Veteran
Well, actually, in my M3 Instruction Book, it plainly states that the infinity lock should be on when installing, removing the lens. Pretty simple language for a simple feature on the lens.:angel:
Roger Hicks
Veteran
Try removing a collapsible lens, or simply erecting it and collapsing it, without using the infinity lock. Sure, you can do it. But it's a LOT easier with!
Cheers,
R.
Cheers,
R.
David.Boettcher
Established
Yes it is. But as David Hughes has pointed out, literature from the 1930s doesn't say this. "Directions Leica Camera Model II" of January 1933 doesn't mention it - it says "The lenses are simply screwed moderately tight into the changing flange." No mention of the infinity lock at all. On the subject of the infinity catch (later on) they just describe how it works, not what its purpose is. The writer of your M3 book has described *a* use for the infinity lock, but not its original purpose.
Again, while this is undoubtedly true, it surely is not the primary purpose of the infinity lock.
Regards - David
peter_n
Veteran
Exactly! I traded my rigid Summicron for a DR because of the damn thing. However I've found out that there are infinity locks and infinity locks. The one on the rigid Summicron is seriously awkward, but the one on the 35 Summicron v.1 is easier to use.It was expressly designed to tick me off when I least expect it.
Pherdinand
the snow must go on
LOL that is a good one. It always amused me how people call it.
Roger Hicks
Veteran
Dear David,
Why not? Quite possibly this was the primary purpose, and it just carried on out of habit. I can't think off-hand of any lenses longer than 50mm with an infinity lock, possibly because longer lenses had enough barrel to grab to unscrew the lens.
I had the infinity lock on my Canon 50/1.2 'reversed', so it was normally unlocked, but I could squeeze it to lock it for removing the lens without rotating the focusing mount as I did do.
I'm not saying that I'm right. I'm just saying that I've yet to see any other mechanically convincing explanation.
Cheers,
R.
Pherdinand
the snow must go on
Your argumentation is flawed from its definition, "infinity" lock.
If you focus at infinity, the DoF will be infinitely large - it will extend from just in front of infinity to way behind infinity - so how much is "half" of that that you say you lose?
t6un
Established
This and the aperture changing and the fact that leaving the focus at infinity also locks the rangefinder arm so it doesn't bounce around when camera gets knocked - there are plenty of reasons, the last one is also true for a rigid lens on an M camera. Additionally, infinity may be the safest setting to avoid burning pinholes into the shutter.
And, the greasy helicoid of the Elmar lens is exposed to the dust in every position except infinity.
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Dr Gaspar
Established
I think it was meant to be used for pick-up lines.
"Have you ever heard about the infinity lock? no? alright, follow me...".
"Have you ever heard about the infinity lock? no? alright, follow me...".
Sparrow
Veteran
Your argumentation is flawed from its definition, "infinity" lock.
If you focus at infinity, the DoF will be infinitely large - it will extend from just in front of infinity to way behind infinity - so how much is "half" of that that you say you lose?
... sorry to be picky; but I'm not sure one can have anything beyond infinity, well except on those kiddies' movies perhaps
David Hughes
David Hughes
Hi,
Interesting that it took them from 1925 to 1955(?) to decide that; and shows that no one can accuse Leitz of jumping in without thinking about it first...
By the way, the early ones without interchangeability of the lenses had one, didn't they? Meaning the hockey stick.
BTW (2) I can't be bothered to read all the books again but I'm certain that they recommend unscrewing and vice versa with the thing far from infinity; something to do with not messing up the RF coupling. Anyway, it's what I always do.
Regards, David
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batterytypehah!
Lord of the Dings
Um, I think we'll give you the Friday afternoon bonus for this one ;-)
Good point.
David.Boettcher
Established
No, I'm not convinced by any of these theories.
The fact that the early models without interchangeable lenses had infinity locks on the body - the hockey stick - is the killer for me. It seems to me there was some optical/photographic purpose Barnack had in mind when he created the hockey stick infinity lock on those early cameras.
When interchangeable lenses were introduced the infinity lock moved to the lens mount, because it had to. And then it gained the other purposes which have been mentioned - but that didn't change its *prime* purpose, the reason it was created - which we don't seem to know!
Regards - David
The fact that the early models without interchangeable lenses had infinity locks on the body - the hockey stick - is the killer for me. It seems to me there was some optical/photographic purpose Barnack had in mind when he created the hockey stick infinity lock on those early cameras.
When interchangeable lenses were introduced the infinity lock moved to the lens mount, because it had to. And then it gained the other purposes which have been mentioned - but that didn't change its *prime* purpose, the reason it was created - which we don't seem to know!
Regards - David
Sparrow
Veteran
... or care? ...