Leica LTM Question about non-permanent inactivation of infinity lock

Leica M39 screw mount bodies/lenses
rajmohan-fotograf

rajmohan-fotograf

rajmohan
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Hi folks,

I have a few LTM lenses with infinity locks, which I find don't help me focus quickly.
Have any of you found an effective method of deactivating the infinity lock mechanism without permanently removing it from the lens (which I don't wish to do)?

Many thanks!
 
With some lenses there is a slot that allows you to unscrew the pin which holds the lock mechanism together. Don't let the spring escape and you can refit it later if you wish. I've done this with Canon 50/1.4 and 50/1.8 LTM lenses and can see this slotted screw on some FSU lenses like the I-22.
 
This is the screw...
U51008I1481201676.SEQ.0.jpg
 
There are enough different designs of infinity lock that there is no "one size fits all" answer. Which lenses are you talking about?

Cheers,

R.
 
mcfingon said:
With some lenses there is a slot that allows you to unscrew the pin which holds the lock mechanism together. Don't let the spring escape and you can refit it later if you wish. I've done this with Canon 50/1.4 and 50/1.8 LTM lenses and can see this slotted screw on some FSU lenses like the I-22.
Click to expand...

Thank you for this and the image.
 
In the past, when I have removed an infinity lock, I put the parts in an empty film can, label it and save it carefully in case I want to restore the infinity lock at a later date. Joe
 
The infinity lock on the Canon Serenar 50mm f1.8 is held on by a slotted screw as in the picture above. The infinity lock on the Leica 50mm f2.0 Summicron collasible is held on by a screw with two small dimples that requires a pointed-tip spanner. Remember these screws have been in place for years and can be hard to remove.
 
rajmohan-fotograf said:
Hi Roger,

The lenses are: Elmar 50 f3.5, Summitar 50 f2, Collapsible Summicron 50mm f2, and Canon Serenar 50 f1.8.

Thank you.
Click to expand...
The Elmar and Summitar have already been covered and I think the Summicron is the same. Dunno about the Canon but some here probably does. EDIT: As indeed has already been shown to be the case -- and I was wrong about the Summicron.

The reason for my original question was that with the Canon 50/1.2, I used a toothpick to jam the lock open but a helpful repairer moved the spring so the lock only came on when pressed, instead of coming off when pressed. This may nor may not be possible with your lenses. I fear it's probably not possible because it looks as if the spring would foul the lock.

Cheers,

R.
 
One of the reasons the infinity lock is there is to take the torque stress while mounting or removing the lens. Otherwise, you put strain on the infinity or near focus stops of the focusing ring, which can put them out of adjustment.

Also, if you do deactivate it or remove it, and you lose the pieces there are consequences. If you go to sell it, the buyer will view your lens as a messed up / tampered with lens, and the sale price will reflect that.

My view is to leave it alone.
 
Robert, is torque a real thing? The infinity stops on these lenses are at least as robust as the little metal tab that catches the infinity lock - and I don't think they started making LTM lenses more robust when they stopped making tabs. I've never heard of an LTM lens going bad this way. I guess you could use a pipe wrench to screw the lens onto the camera.

As to losing the pieces, I totally agree.

Dante
 
I have a Canon 50 1.4 LTM that was completely off in focusing. It turns out that the focus stops were out of adjustment. Since these stops need to be in a very precise location, why put strain on them every time you change lenses?

The infinity lock is a robust little gizmo that doesn't directly affect your focus / rangefinder accuracy. Better for the infinity lock to take the strain.
 
My initial thought was to just place a tiny spacer between the infinity lock screw and its base, so that it is pushed away from the little metal tab that catches the screw. This way, the screw/fittings are not tampered with, and the lens can be focused to infinity without catching on the tab at infinity. And removal of the little spacer would restore the lens to its factory state.

But from the feedback so far, it sounds like this is not something other users have successfully achieved, so perhaps I am off the mark with this idea.
 
Dante_Stella said:
Robert, is torque a real thing? The infinity stops on these lenses are at least as robust as the little metal tab that catches the infinity lock - and I don't think they started making LTM lenses more robust when they stopped making tabs. I've never heard of an LTM lens going bad this way. I guess you could use a pipe wrench to screw the lens onto the camera.

As to losing the pieces, I totally agree.

Dante
Click to expand...
Dear Dante,

Your reaction is exactly the same as mine.

Cheers,

R.
 
rajmohan-fotograf said:
My initial thought was to just place a tiny spacer between the infinity lock screw and its base, so that it is pushed away from the little metal tab that catches the screw. This way, the screw/fittings are not tampered with, and the lens can be focused to infinity without catching on the tab at infinity. And removal of the little spacer would restore the lens to its factory state.

But from the feedback so far, it sounds like this is not something other users have successfully achieved, so perhaps I am off the mark with this idea.
Click to expand...
No, I don't think it is possible: the spacer would probably foul the tabs on the lens mount. I thought of the same thing but decided it was too difficult.

Then again, I find it very easy to press down on the button when using Elmar-type infinity locks, possibly as the result of years of practice.

Cheers,

R.
 
Roger Hicks said:
No, I don't think it is possible: the spacer would probably foul the tabs on the lens mount. I thought of the same thing but decided it was too difficult.

Then again, I find it very easy to press down on the button when using Elmar-type infinity locks, possibly as the result of years of practice.

Cheers,

R.
Click to expand...

Thanks, Roger - I'll keep practicing, and with time, dealing with the lock might become second nature :)
 
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