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LTM adapter TYPE question


KFo

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Hi all:

I’m hoping the deep knowledge here can answer this for me.  I’ve searched around and can’t find an answer...

I’m a M10 shooter.  I’m adapting screw mount lenses to that system.  In my searching for LTM-M adapters I’ve ran across various “types” of adapters.  For example “TYPE III” LTM adapter.  It leads me to wonder if there are TYPE II and TYPE I adapters and what the differences would be between all them.

What is the story with these adapter types?

Regards,

Kevin

 

 

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I don't know of an official "TYPE I/II/III" denomination of LTM adapters… but Leitz indeed made three different adapters :

IRZOO - 14097 for 35/50mm lenses (and some are marked "28-50")

ISBOO - 14098 for 90mm lenses

ISOOZ - 14099 for 135mm lenses

So that the correct frame for lens length would appear in the Viewfinder.

But for usage on a digital Leica, the old Leitz original adapters above quoted  are not the best option : most (not all) of them have a cutout around the external diameter, made for allowing the use of lenses with the old style focusing knob with infinity catch (let say... the "Elmar 50" knob).  This cutout poses a problem on digital Leicas : it Leaves partially uncovered the 6 bit code reading strip on the body flange : you cannot use lens recognition/correction.  Many modern adapters  by various manufacturers (mostly China-made) on the contrary do not have this cutout, so that the 6 bit code can be regularly used, provided that it is present on the adapter itself : and indeed several of those "new" adapters do provide 6 blank milled marks in the correct position, so that one can compose, using black & white enamel, the code he likes  : the old Screw Mount lenses of course do not have a code of their own… but of course one can do reasonable approximations (an old Elmar 50 LTM coded as an Elmar M 2,8 50,  and similar)

  

 

Edited by luigi bertolotti
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vor 41 Minuten schrieb luigi bertolotti:

...(an old Elmar 50 LTM coded as an Elmar M 2,8 50,  and similar)

Unfortunately this example isn’t possible without „tweaking“ the good old 5cm Elmar with LTM, or tricking the electronics of the digital M.

The Elmar has the focussing knob which needs the cutout on the adapter. It would be a sacrilege to change the focussing knob so that it won‘t collide with adapter. 

You might trick the camera by attaching some black tape on the place where the 6-bit-code is read, so no light gets on the sensor for the code. Only then you can select a certain lens from the menu to apply the data. Though this isn‘t a very practical solution.

Certainly an old Elmar does not need any correction. The code is only useful for having some data in the exif of your foto-files, and for some functions when you use a flash or auto ISO.

I fear one has to decide: either using an old Elmar and don‘t bother about the all the 6-bit-code stuff - or using a lens which has no focussing knob. I‘d always prefer the first option. 

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This is quite interesting.  So I think, based on the answers so far, the so called TYPE III adapter are 6-bit coded with no infinity lock.  Then there is a version of the LTM-M adapter which incorporates a cutout for the infinity lock, either at 6 or 7 o’clock positions.

I have an LTM-M adapter that is notched, no 6 bit-coding: when I line it up with my Summaron 28 (a M-mount version) the notch doesn’t line up with the inifinity lock position.  On the Summaron, the infinity lock is at 7 o’clock.  The notch on the adapter is at about 9 o’clock.  I suppose it’s possible the the maker of the adapter had no idea the purpose of the notch.

What purpose would a notch extending all the way around to 9 o’clock serve?

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Here are the three "cutout" shapes of ltm to M adapters. Type I is in the center, with the cutout for the lens release along the bottom edge, as was needed for 50 & 35 Elmars and other lenses with the infinity lock close to the flange. Later 50mm and longer lenses didn't need the cutout, as the lock tab was farther away from the flange, so the Type II (on the left) with no cutout could be used for them, and was cheaper to make. The Type III (on the right) is only from aftermarket sources, and leaves the cutout around the lower "7 o'clock" position where the infinity lock could interfere, but still leaves the 6-bit sensor area of the camera covered. Note that  types I & II have the circular notches at the same locations 120 degrees apart around the edge, as an old style rear lens cap had nubs on the back that could fit these notches to remove an adapter that was stuck in the body. One notch should always be at the top of the lens mount when properly mounted, as this orients focusing cam correctly, if the ltm thread is properly cut. (I've seen some cheap adapters where the ltm thread start was off position and the lens wouldn't orient correctly.)

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Edited by TomB_tx
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Fantastic writeup!!!!  Thank you.

I had been thinking that the type III was an aftermarket setup.

as a.noctilux mentions I’ve worried that removing the type III in the event it was a little stuck could be an ordeal.  That Kipon is the one I have now and am using.  The Kipon is less than perfect, much less in fact.

So Leica never made an adapter that dealt with the issue of the optical sensor on 6-bit cameras?  It was left to the aftermarket.

It looks like a type IIa would be useful.  Same as type II but with the removal notches offset (maybe -30deg)sufficiently to miss the optical sensor area and providing place to 6-bit code at home.

Regards,

Kevin

 

Edited by KFo
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14 hours ago, a.noctilux said:

Strange adapter at right, so if this Kipon adapter is stuck on the camera mount, there is no way to remove it

with the old (or Voigtlander cap lately) lens cap with three nubs.

You can probably still get the adapter out with a Voigtlander or old Leitz cap. I tried it, fitting the top nub in place and a second nub in the cutout where it fits properly, and even though the 3rd nub holds that edge of the cap up a bit, pressing the cap tight against the body the top nub still got enough of a grip to remove the adapter. I have a 1955 M3 where the mount is extremely tight on the lens bayonet, and I wouldn't try this adapter in that camera, as the one "driving" nub might shear off from the high torque, but on a more typical M body it should be fine.

A cutout for the 3rd nub would just miss the pits for the 6-bit coding, but would be very close, so it might mess up the reading anyway.

Rayqual (sold by Camera Quest since Voigtlander quit making their ltm adapters) also makes a Type III adapter that is quite good quality, but it also doesn't have the 3rd nubbin cutout.

I have a Chinese 6-bit coded adapter from (on eBay) than as NO cutouts for the nubs to remove an adapter from the camera. They still sell these, but I'd only use it to convert an M to permanently use ltm lenses!

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15 hours ago, TomB_tx said:

 if the ltm thread is properly cut. (I've seen some cheap adapters where the ltm thread start was off position and the lens wouldn't orient correctly.)

 

Don't assume this is necessarily a fault, standard and wider LTM lenses are often meant to be offset to the left and not with infinity at top dead centre so you can see the infinity mark when looking around a period accessory finder from above. It is debatable whether you'd still want it offset on an M body, but it goes that an adapter that mounts an offset lens with infinity at top dead centre is even more 'faulty'.

Edited by 250swb
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11 minutes ago, 250swb said:

Don't assume this is necessarily a fault, standard and wider LTM lenses are often meant to be offset to the left and not with infinity at top dead centre so you can see the infinity mark when looking around a period accessory finder from above. It is debatable whether you'd still want it offset on an M body, but it goes that an adapter that mounts an offset lens with infinity at top dead centre is even more 'faulty'.

Agreed - most ltm lenses are offset from vertical by design, but I've had some cheap adapters where the position is different from others because the thread start wasn't closely controlled This puts the cam follower contact at a different place than it should be, and depending on the cam grind can cause mis-focus.

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The offset for the focus mark of the LTM lens makes sense to me when there is no adapter being used.  With adapter, I think things should just line up to the top more or less.  I have a Kipon that is offset slightly.  The offset is in the wrong direction to facilitate viewing the focus mark with a view finder mounted.  It looks sloppy, but probably doesn’t matter much.

Of course someone could make a TYPE IIaVf; an adapter specially made to offset the focus mark for wide angle use with a view finder.

After spending a little time this morning looking at my lenses, it wouldn’t matter at all what the orientation of the lens is on the camera body.  On the back of the lens the surface that drives the RF follower is flat; that is it has no cam action.  At least not on the 6 lenses I”ve got.

I’ve not ever messed around with adapting non-native lenses and I’ve been playing with photography since the 80s.  As with many things appreciating and understanding the exact details makes a big difference.

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A number of the Leitz lenses I have from the 1950s-70s have a slight slope ground into the cam surface. This is because the exact focal length of each individual lens could vary a bit due to element tolerances, and a single cam shape could not work exactly with them all, unless they had slighly different thread pitches to match. So each cam was finished ground to adjust for each lens. Therefore, if the cam follower contacts the cam at a different alignment point than designed the focus would be slightly off.

Since these dates are after the M3, most are M mount and won't use an ltm adapter of course. However I have two ltm 50mm 2.8 Elmars, and one has a flat cam while the other has a slight slope ground on it. So it looks like the flat cam is probably an exact nominal FL, while the other is a bit different and needed a slope adjustment.

I suspect this technique originated after the switch to the M mount, since the bayonet mount oriented the lens EXACTLY, so a slope grind would be repeatable on all bodies, while an ltm mount could vary a bit (and more due to wear, etc.) The 2.8 Elmar was introduced with the IIIg, after the M3 & M2, so the grinding adjustment may have started about that time. The ltm lenses I have from the 1930s & 40s do seem to have flat cam surfaces.

Some lenses, such as the Summicron-C (40 mm) and Elmar-C (90)mm used a sloping cam for the Leica CL, so lens alignment is critical for those IF you are focusing by RF. The same is true of the Summarit 2.5 35 & 50mm lenses, and the 7-Artisans I've tried. Of course, all these are M mount so no adapter to mess things up.

The Voightander ltm lenses I have do have flat cams.

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20 hours ago, a.noctilux said:

Strange adapter at right, so if this Kipon adapter is stuck on the camera mount, there is no way to remove it

with the old (or Voigtlander cap lately) lens cap with three nubs.

I was looking around and found this on *bay.  Looks like it provides driver bosses for the removal of the adapter from the camera mount integrated into the rear lens cover.

 

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2 hours ago, TomB_tx said:

.snip.

Since these dates are after the M3, most are M mount and won't use an ltm adapter of course. However I have two ltm 50mm 2.8 Elmars, and one has a flat cam while the other has a slight slope ground on it. So it looks like the flat cam is probably an exact nominal FL, while the other is a bit different and needed a slope adjustment.

.snip.

I stand corrected, I forgot to look at my 90mm Macro-M Elmar (hidden in the day bag).  It is cammed (sloped) on the focusing surface.  It’s also marked with the exact focal length.  Do your 50mm Elmars have marking to indicate the exact focal length?

 

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Edited by KFo
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When I  am buying an adapter to use one of my many LTM lenses with digital Leica cameras or lens adapters which have a 6 bit reader, I stick to Rayqual adapters. They are not cheap but when I have checked them with a 1/10,000 inch reading micrometer, they are very accurate (even better than original Leica made ones). They are anodised in a dead black finish with a slot to add manual lens coding, so that you don't get the very irritating message on the screen of: "No lens detected". I use these Rayqual adapters constantly with my two late 1999 year Special Edition Leica LTM lenses, my 50mm/f2 Summicron V-SE and 50mm/f1.4 Summilux III-SE. 

I would love to find one of those back caps with the three lugs, as I am frequently struggling to get my LTM to M adapters out of camera bodies, when they have not come off with the lens. 

Wilson

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