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Question about non-permanent inactivation of infinity lock
Old 12-08-2016   #1
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Question about non-permanent inactivation of infinity lock

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!
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Old 12-08-2016   #2
mcfingon
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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.
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Old 12-08-2016   #3
mcfingon
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This is the screw...
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Old 12-08-2016   #4
Roger Hicks
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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.
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Old 12-08-2016   #5
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Quote:
Originally Posted by mcfingon View Post
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.
Thank you for this and the image.
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Old 12-08-2016   #6
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Quote:
Originally Posted by Roger Hicks View Post
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.
Hi Roger,

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

Thank you.
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Old 12-08-2016   #7
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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
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Old 12-08-2016   #8
View Range
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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.
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Old 12-08-2016   #9
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Quote:
Originally Posted by rajmohan-fotograf View Post
Hi Roger,

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

Thank you.
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.
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Old 12-08-2016   #10
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Thanks everyone, this is all very helpful information.
Cheerio!
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Old 12-08-2016   #11
Dante_Stella
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Use a bigger screwdriver and grind it down to fit. Seen plenty of these locks butchered.
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Old 12-08-2016   #12
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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.
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Old 12-08-2016   #13
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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
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Old 12-08-2016   #14
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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.
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Old 12-08-2016   #15
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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.
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Old 12-08-2016   #16
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The torque of removing/installing one of these lenses is taken by the stop screws on the flange.

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Old 12-08-2016   #17
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Quote:
Originally Posted by Dante_Stella View Post
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
Dear Dante,

Your reaction is exactly the same as mine.

Cheers,

R.
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Old 12-08-2016   #18
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Quote:
Originally Posted by rajmohan-fotograf View Post
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.
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.
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Old 12-08-2016   #19
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Quote:
Originally Posted by Roger Hicks View Post
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.
Thanks, Roger - I'll keep practicing, and with time, dealing with the lock might become second nature
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Old 12-08-2016   #20
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Actually felt the same way with infinity locks, but it does become second nature after some use!
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Old 08-11-2018   #21
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Quote:
Originally Posted by mcfingon View Post
This is the screw...
This thread was great help. And this article.
Now I have Canon 50 1.8 with smooth focus, easy switching apertures and not only infinity lock bypassed, but focus tab traveling from 3 to 15 O'clock, instead of having focus tab all way up on M mount cameras at one meter.
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Old 08-11-2018   #22
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That's good news Kostya. I don't own one, but after shooting a couple of frames with one, I've got the impression that the 50/1.8 Canon is a good lens.
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