How to mount a screw mount lens on LTM body.

[Richard G]

I only read this recently. No doubt long-time users know it. I am not sure I would have discovered it until I saw it declared explicitly.

With the lens locked at infinity, start the engagement with the infinity lock pointing towards the RF window on the left as you look at the camera. The lens enters the thread almost immediately, no fiddling around. My pleasure in using these little gems increased another notch when I learnt this.

It works for my 1932 50mm Nickel 11 o'clock Elmar as well as my later "7 o'clock" 1950s 50 Elmar and 35 Summaron.

 

[Rob-F]

Discovering these little "tricks of the trade" is one of the pleasures of owning the older Leica gear. Getting the hang of loading an LTM is another. You have some nice classic lenses there!

 

[bucs]

It Works!!!!!!!

 

[DanskDynamit]

so, for those with Leicas without a rangefinder it would be to place the infinity lock at kind of 11 o'clock?

 

[Richard G]

so, for those with Leicas without a rangefinder it would be to place the infinity lock at kind of 11 o'clock?

Good question. I don't know. Presumably the idea of a screw mount interchangeable lens camera even before the standardisation of lens to film plane distance of the early 1930s would have included some standardisation of the way to mount the lens, so I hope the answer is yes.

 

[lynnb]

Thanks Richard. From my Leica Instructions for the use of the Leica Camera models c, f and g (Ernst Leitz Wetzlar and London):

CHANGING LENSES
All LEICA lenses are interchangeable and will fit any LEICA camera (except very early models). To change a lens hold the camera horizontally, lens pointing upwards, in the left hand and with the right hand grasp the lens close to the camera body and unscrew it by turning anti-clockwise. To fit the alternate lens, hold the camera as described and present the lens to the flange in such a way that the focusing lever is directly in front of the viewfinder window. Engage the threads by a slight anti-clockwise turn and screw home by turning the lens (into the*) mount in a clockwise direction. The lens tube should be drawn forward and locked before being fitted to the camera.

*my addition, seems like a misprint.

 

[newspaperguy]

Maybe I woke up grumpier than usual, 😱

but it seems to me y'all are over-complicating the procedure. :bang:

Look at the last sentence in the Leica instruction that Lynn posted.

Be sure your lens is fully extended (set to the closest focusing distance).

That way you're not fighting the RF cam in the camera and the lens goes in straight with no hassle. :angel:

 

[sreed2006]

Two Summaron 35/3.5 lenses I have do not work this way; the threads engage when the infinity lock points at about 4:00 o'clock.

An Elmar 50/3.5 and an Elmar 50/2.8 do as you describe, with the infinity lock pointing at about 11:00 o'clock.

An Elmar 90/4 and a Hektor 135/4.5, neither of which have infinity locks, catch threads quickly when the center of the distance scales are set at 6:00 o'clock.

Still, these things are good to know. I have fumbled with them far too often, and now I know!

P.S. This is for lenses mounted to a IIIg.

 

[Robert Lai]

Actually, the key point of the Leica statement is to give the new lens an anticlockwise rotation until you feel the start of the threads mate. Then you can rotate clockwise to tighten down the connection.

This is key to prevent stripping any thread: whether for filters, nuts and bolts, or pipe fittings. Anyone who has had some shop training will do this as a matter of habit.

 

[andybrown]

Setting the lens to it's closest focus is the way I do it now. Old dog, new tricks, just from 2 weeks ago.

 

[rfaspen]

I like it to be simple, and I can't seem to remember any "rules".
I set the lens to closest focus, place lens on body and turn anti-clockwise a bit, until I feel the "click" and then turn clockwise. Has worked perfectly every time, every time, for years (a number of which I will not disclose).

 

[css9450]

This is key to prevent stripping any thread: whether for filters, nuts and bolts, or pipe fittings. Anyone who has had some shop training will do this as a matter of habit.

The funny part, however, is when passers-by see what you're doing and they panic and insist on warning you you're "turning it the wrong way!"

 

[davidnewtonguitars]

Because the lens mount threads are "single start" they really can only be mounted one way.
If you strip or cross-thread the mount, you must be miss-aligning and forcing things badly.

 

[David Hughes]

Hmmm, you'd have to work really hard to cross thread the thing...

And, 2, it shows the advantage of RTFM'ing and now I wonder if anyone does...

Regards, David

 

[Richard G]

My first LTM was a Leica II for which, strangely, there is no manual. Interestingly, the manual I have downloaded is for various models and its text differs a little from Lynnb's quote above, and alludes to the viewfinder window orientation working for 35 and 50mm LTM lenses.

I agree with recent posters that it would be hard to strip the LTM thread. The initial anticlockwise movement advice of the manuals is a universal precaution which in practice (after practice) is unnecessary. Similarly, close focussing for mounting would be such a nuisance. The lens locked at infinity gives a nice stable base to hold. Having the close-focussed freely moving focus lever no longer useful for direct rotation of the lens mount seems counterproductive to me.

 

[David Hughes]

Hi,

You can find a model II manual here as a PDF;-

http://www.cameramanuals.org/leica_pdf/leica_model_ii.pdf

After reading these threads I wondered and got out all my Leitz and Leica manuals (from 1928 to the M9) but the only way they suggest is unscrewing and so on, not one mention of 11 o'clock. The NY version of the IIIc manual does mention turning the lens backwards to find the start of the thread. (I've never seen a British version of the IIIc manual, btw.)

Also of interest, and probably aimed at Contax, are comments about the accuracy of the screw thread compared to a bayonet...

Regards, David

 

[Richard G]

Thanks David for that Leica II manual. My rewind knob was stuck down when I got mine and I didn't know if this was normal or not. I tried everything I could to find a Leica II manual. I should have asked you. I fixed the rewind nevertheless.

On mounting the lens I think we are all saying roughly the same thing. The manual has to have the most conservative advice, starting at the viewfinder window, rotating backwards to find the start of the thread and then turning clockwise. I'm just skipping the first bit and moving from 11 o'clock straight into the thread.

 

[ray*j*gun]

Plus one on this I have found that it helps a ton.

Maybe I woke up grumpier than usual, 😱

but it seems to me y'all are over-complicating the procedure. :bang:

Look at the last sentence in the Leica instruction that Lynn posted.

Be sure your lens is fully extended (set to the closest focusing distance).

That way you're not fighting the RF cam in the camera and the lens goes in straight with no hassle. :angel: