HuubL
hunter-gatherer
Just read in the description of a (M2 type) Summaron on the bay that it could easily be converted from M to LTM mount by removing the M bayonet which was fixed with only one little screw. This would make the summaron an ideal lens to use on both my LTM bodies and my M4's. Any body knows if this is true?
edodo
Well-known
Yes I got a friend who bought one for 360€ in a shop in Paris. A steal if you ask me! He said to me that earlier Summaron 2.8 M were made this way because they were in reality screw Summaron that had the mount upgraded.
HuubL
hunter-gatherer
Sorry for reviving an old thread. I posted the above question at the time I had only a later (1966) Summaron. That one did not have a set screw fixing the M-mount flange to the rest of the lens body. After another thread yesterday I realized that my new (1959) Summaron did have the set screw despite the fact that the lens focuses to .7m, which is generally an indication for a Summaron to be specifically made for M bodies. Today I verified that the M-mount flange can indeed be removed revealing an LTM thread allowing the lens to be screwed on LTM bodies. Is this part of the common Leica knowledge here?
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payasam
a.k.a. Mukul Dube
I am far from the most knowledgeable person here, but I do know a bit of this and that: and I had not heard of this possibility. I cannot understand why this should have been done when M adapters have always been available.
HuubL
hunter-gatherer
Thanks Mukul,
In my opinion the removable flange of the early Summaron (and Summicron as well) is more like a dedicated (later ?) M-adapter. I'll see if I can post pictures later. Also, I have to check that with the flange removed, the Summaron focuses correctly on an LTM body.
ferider
Veteran
As far as I remember when I tried, the M mount on the Summaron is thicker than a correct M/LTM adapter. Meaning you can remove it and mount the lens to an LTM Leica but it will not focus to infinity.
They do that on the bay, by removing goggles and trying to sell the lens as the more expensive LTM version. However, focus without goggles will be off even worse. You can distinguish the different versions via min. focus distance of the lens (.7m, .65m and 1m).
Roland.
They do that on the bay, by removing goggles and trying to sell the lens as the more expensive LTM version. However, focus without goggles will be off even worse. You can distinguish the different versions via min. focus distance of the lens (.7m, .65m and 1m).
Roland.
HuubL
hunter-gatherer
Not in my case Roland. My Summaron flange and a regular M-mount adapter have their off-camera lens surface at the same distance from the body, meaning that the base of the LTM lens is exactly at the same distance from the film with both mounts. Moreover, when I screw my "LTM Summaron" onto a real Leica M-mount adapter, the "thickness" or front to mount distance of the lens is exactly the same in both cases. Well, I think the definite proof can only come from trying.
Tom A
RFF Sponsor
I haven't done that for years - but if my memories serves me right (it rarely does) - you have to re-calibrate the focus as the back of the lens "sits" deeper into the camera. Not a biggie - but something to consider.
fbf
Well-known
Sorry to hijack the thread but could the same thing be done with the m3 type I 35 cron ? I see people remove the goggles and sell them as the more expensive m2 type. Would it work properly IF the focus is adjusted or can it be adjusted at all?
ferider
Veteran
HuubL
hunter-gatherer
payasam
a.k.a. Mukul Dube
Ferider: "As far as I remember when I tried, the M mount on the Summaron is thicker than a correct M/LTM adapter. Meaning you can remove it and mount the lens to an LTM Leica but it will not focus to infinity."
Roland, wouldn't the lens then focus beyond infinity?
Roland, wouldn't the lens then focus beyond infinity?
HuubL
hunter-gatherer
Ehh.., No I don't think so Mukul. Placing a lens further away from the camera makes it focus at closer range (compare, bellows, macro lenses, close-up mounts, visoflex, etc.)
payasam
a.k.a. Mukul Dube
If a mount thicker than the standard M adapter ring is needed, then when the lens is mounted on a screw body without that thick mount, it will be closer to the film plane than it needs to be. This is the reverse of an extension tube or bellows.
HuubL
hunter-gatherer
ehh..., I stand corrected Mukul. I interpreted this inverted 
HuubL
hunter-gatherer
A brief update. I just developed a couple of films shot with the Summaron mounted on my Leica CL through its M-mount and with the M-mount removed screwed on my IIIg. I shot at F/2.8 and F/4 at close range (< 1m) and at infinity. I only inspected the negs thus far, but all shots look excellently sharp. I hope to post scanned pictures later, but as far as the results look now, this certainly looks like a double mount lens!
HuubL
hunter-gatherer
In the meantime I found out that of approximately 20000 M2-type M-mount F/2.8 Summarons some 5000 early Summarons were made as dual mounts with removable M-mounts. Note, these are true M2-type Summarons with a distance scale starting at 0.7m (2'4"), not the full LTM version or M3-type Summaron with the goggles removed. On the IIIg the shortest distance that the rangefinder can get into focus is approximately 0.8m.
I scanned some negatives (Fomapan 200 in Rodinal 1:50, 20 min). Here a few examples of close-up (85 cm) and infinity shots with the Summaron screwed onto the IIIg.
The first photo (@ F/2.8) shows the Summaron mounted on the IIIg as shown on my MacBook. In the other two (both @ F/4) the focus is close-up and at infinity, respectively. Sorry about the water stains and other junk.
I scanned some negatives (Fomapan 200 in Rodinal 1:50, 20 min). Here a few examples of close-up (85 cm) and infinity shots with the Summaron screwed onto the IIIg.
The first photo (@ F/2.8) shows the Summaron mounted on the IIIg as shown on my MacBook
. In the other two (both @ F/4) the focus is close-up and at infinity, respectively. Sorry about the water stains and other junk.