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Explain screwmount to M adapters?


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Could the knowlegeable Leica users please explain the different sizes of adapter rings, for using screwmount lenses on M cameras? I believe there are 2 or 3 sizes of these M adapters and don't know why a single size is not OK for all screwmount lenses. Is it because screwmount lenses need to be mounted at slightly different distances (with different-thickness adapters) from the M body?

And, are genuine Leica M adapters recommended (better) compared to generic adapters?

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There are not 3 different ‘sizes’ of these adapters rather, there are adapters which activate different frame lines in Leica M bodies.

 

One of the lens’ bayonet lugs mates with a lever in the Leica M body and as you lock the lens in place, the lug moves the lever to a position which brings the appropriate frame line(s) into view. The lug for the 35/135mm lines is the shortest, as that is the default position for the frame lines - when there is no lens attached to the camera, those two frames will display. The 50/75mm lug is slightly longer and the 28/90mm one is the longest.

 

The adapters work the same way as Leica M lenses so, if you have 50mm thread lens, the correct adapter for it would be one for 50mm lenses. Theroretically, an adapter for a 35mm lens could be used as well - it would provide correct focus but, would not activate the correct frame line for the 50mm lens.

 

A simple explanation - the adapter works the same way as a bayonet mount lens by activating the frame line for the lens it was designed for.

 

Generally speaking, genuine Leica adapters are better than their generic Chinese or Japanese equivalents. However, with the advances in machining technology, a well-made generic adapter should work just as well as the original Leica one. Don't forget that the original Leica adapters have not been produced for close 40 years.....

 

Cheers from an ex-Montrealer,

 

Jan

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Jan explanations are excellent as always... I add just an observation about Leica (Leitz, better to say) original adapters : they were very well made, and also engraved with the focals length they were made for, i.e., the frames they activate into Viewfinder ; this makes them the best to use for classic film M cameras : BUT, in the context of the modern line of Digital Leica Ms, the original Leitz adapters can have an important issue : most of them have a cutout along the external diameter (made to avoid interference with the focusing knob of some LTM lenses) , and this cutout is coincident, when adapter is mounted, with the area of the lens mount in which the digital Ms have the 6-bit code sensors : this definitely prevents the lens auto lens recognition on digital Ms... the adapter simply cannot be coded : on the contrary, most of the modern 3rd party adapters don't have this cutout (and many of them have also the milled recesses for 6 bit coding).

On the Leica M 240 the "classic" adapters with cutout not only do prevent 6 bit coding, but also inhibit the usage of Live View functionality... the light leak caused by the cutout "fooles" the reading system and Liveview simply cannot be activated.

In conclusion, to use LTM lenses on a digital M is generally better to have a well made 3rd party adapter.

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.

In conclusion, to use LTM lenses on a digital M is generally better to have a well made 3rd party adapter.

 

And use the ones whith 6bit coding milling, after that for those lenses with the infinity locking just screw on the lens on the adapter in the unlocked position.

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....On the Leica M 240 the "classic" adapters with cutout not only do prevent 6 bit coding, but also inhibit the usage of Live View functionality... the light leak caused by the cutout "fooles" the reading system and Liveview simply cannot be activated.

In conclusion, to use LTM lenses on a digital M is generally better to have a well made 3rd party adapter.

 

Good advise to prevent that the versions of original Leitz adapters, which do not have the cutout, disappear completely because everybody wants them

 

The original 9cm-adpater without cutout is not too difficult to find, because most did not have the cutout; here the version with cutout, which you need for the 1:5.6/2.8cm Summaron is rather hard to find.

 

The original 3,5cm-version, which works for 13,5cm as well is rather rare without cutout, though it exists.

 

But I have never seen the version for 50mm without cutout. Does it exist at all? I fear, it doesn't, for your needed the cutout to use the focussing knob for the 5cm Elmar.

 

BTW: do you really use LiveView and/or coding for screw-mount lenses?

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Some examples there but not exaustive, different shapes and engraving the first one in the second raw is engraved 21 - 35 for the M2 !

the last on the right of the first raw is specially fitted for a lens with the same s/n

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On a Summarex you can use the 90mm adapter - usually without cutout.

 

Does Liveview or the electronic viewfinder help you to focus it more easily than by rangefinder?

 

When I got the Summarex I was sure that i'd never be able to focus it wide opened with th M9. Though to my surprise I found it easier than with a 75mm Summicron - the very long focus throw is essential, even if it slows you down.

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On a Summarex you can use the 90mm adapter - usually without cutout.

 

Does Liveview or the electronic viewfinder help you to focus it more easily than by rangefinder?

 

When I got the Summarex I was sure that i'd never be able to focus it wide opened with th M9. Though to my surprise I found it easier than with a 75mm Summicron - the very long focus throw is essential, even if it slows you down.

 

Hum... hard to give a definite answer, having M+EVF from December 30th (evening...

And, it is definitely better than Visoflex with 200 & over... provided that you don't use EVF magnification... 5x and moreover 10x give highly unstable image in the EVF, not surprisingly (and this applies to 90 and 135 too)

Edited by luigi bertolotti
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Thank you Leica users for explaining to a new Leica user the LTM (lens) to M (body) adapters. The trigger of the correct viewfinder frames is obvious now that I see it written, but since I do not have an M body (only my IIIf), I have much to learn about the M family.

You also provide good advice about future use of the old (but good quality) screwmount lenses on modern digital M cameras. My son (a documentary film maker in Berlin) uses an M8 for his photography, and at Christmas bought a lovely, black, little-used M9 that Montreal's Leica specialist dealer (Camtec Photo) had received on trade. So I will look for the most-useful M adapter rings for him to experiment with my lenses on his modern cameras, during his visits.

My next equiry - about Leica cases - will come soon. I appreciate this Forum and the opportunity to learn from many Leica people around the world.

Enjoy photography in 2014, some of it with film!

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my feeling, at the moment, is that it is useful on static situations... if you have to act quickly, RF is still better... with usual difficulty to nail focus when you work with 90 at f 2...

And, it is definitely better than Visoflex with 200 & over... provided that you don't use EVF magnification... 5x and moreover 10x give highly unstable image in the EVF, not surprisingly (and this applies to 90 and 135 too)

 

I agree, use the TXBOO for the EVF

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  • 3 weeks later...
And use the ones whith 6bit coding milling, after that for those lenses with the infinity locking just screw on the lens on the adapter in the unlocked position.

 

Could Mr. Braconi or others who have used 1950s screwmount lenses (specifically the 5 cm Elmar and Summitar, with infinity-focus knob) on a modern M8 or M9 camera, suggest the proper modern adapter rings (with 6-bit coding area, and allowing the LiveView to function) to purchase?

Product ID, dealer or eBay seller names would be useful.

Thank you for your suggestions.

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  • 8 months later...

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