Safe to collapse a Summitar in LTM mount on M-P 240?

[alfisti71]

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I just got a Summitar from 1951, in LTM mount. Is it safe to collapse and open it, while it is mounted on my M 240?

 

Thanks!

[IkarusJohn]

2 hours ago, alfisti71 said:

I just got a Summitar from 1951, in LTM mount. Is it safe to collapse and open it, while it is mounted on my M 240?

 

Thanks!

No

[dpitt]

Always mount/dismount extended.

If the barrel is in good condition (i.e. if it slides snugly in and out), you can collapse it when mounted on any digital M. Remember to extend before dismounting because it might touch the sides inside of the mount otherwise.

If you hesitate...
Some people add a rubber collar ring on the extension tube so that it collapses a few mm less than normal. e.g. a dymo 3D tape can do the job.

[UliWer]

 

[alfisti71]

thanks all. In looking at the FAQ (thanks Uli) it LOOKS like the Summitar is fine to collapse on the M 240. Given the measurements it seems it's one of the lenses that is not problematic.

My concern of course is that I'll put it on, and unmount it while collapsed, and do damage. But it LOOKS like it measures clear of everything. 

I may put a ring around the mount to prevent it from collapsing all the way, just in case.

Thanks!

[alfisti71]

6 hours ago, dpitt said:

Always mount/dismount extended.

If the barrel is in good condition (i.e. if it slides snugly in and out), you can collapse it when mounted on any digital M. Remember to extend before dismounting because it might touch the sides inside of the mount otherwise.

If you hesitate...
Some people add a rubber collar ring on the extension tube so that it collapses a few mm less than normal. e.g. a dymo 3D tape can do the job.

Thanks. This sounds like a good plan. I would like to be able to mount/dismount without extending - not because I NEED to, but because I feel like I'm likely to forget to extend it at some point, and I do not want to cause any damage. It seems little shim to keep it from collapsing all the way is cheap insurance. 

[UliWer]

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vor 9 Minuten schrieb alfisti71:

Given the measurements it seems it's one of the lenses that is not problematic.

Well, I am not so sure. As I explained in the FAQ posting, the real risk is that the rear part of the lens touches and perhaps scratches on the roller which activates the rangefinder. When I use the Summitar with my screwmount Leica II and collapse it - the lens was made to collapse on screwmount bodies! - I sometimes feel a resistance inside: the lenses rear is hitting the little wheel which is at the same position  in the II as in any analogue or digtital M. My Summitar has some sharp edges at it's tube's end. It works if I move it a little bit, and when its users for 80 years or so could live with it, I should not have too many problems with it.

Though of cause you can use any lens with retractable tube lens uncollapsed: they are still much smaller uncollapsed than any comparable modern lens.

[Borna]

Does it not say in the instruction manual? If I am not mistaken, in mine it said which lenses that was not compatible with the camera 

[IkarusJohn]

I have the 50/2 Summitar LTM from 1948, with the Voigtlander adapter.  With my TL2, the end of the lnes brushes against the housing inside the lens mount if I collapse it.  I have not been prepared to collapse it inside my M cameras (as the manual says not to) for fear of damaging the shutter, the roller or the sensor on the Monochrom or the M10-D.

I prefer to have a ring or thick piece of string or whatever else I find around the house tied around the tube so it doesn’t go too far in.

I see no point in taking the risk …

[alfisti71]

37 minutes ago, Borna said:

Does it not say in the instruction manual? If I am not mistaken, in mine it said which lenses that was not compatible with the camera 

Thanks - I got mine second-hand and did not get an instruction manual. I just viewed it online, and here is what I see: 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

I think that is the SAFEST approach, but - maybe not the full picture. I absolutely don't want to damage the camera (or lens) but if it is in fact OK to retract, it could be convenient.

Thanks

[UliWer]

vor 34 Minuten schrieb IkarusJohn:

for fear of damaging the shutter, the roller or the sensor on the Monochrom or the M10-D.

I shall not propose to collapse any lens in a digital M body ...

... though any fear that this will damage the shutter or even the sensor is not justified. Please think of the M3: it originally had standard lenses which were collapsible - 50mm Elmar and Summicron, even a collapsible 90mm Elmar. There were still many Summitars in usage with the well known adapters: Did any of the lenses hit the shutter - or even the film! - of an M3? No, and nobody feared they would.

Now if you measure: which camera has a shorter distance between the flange and the two metal ridges which are immediately in front of the shutter? is it the M3 or a digital M?

I measured: the distance is considerably shorter for an M3 than for a digital M because the two ridges were much fatter.

So if the shutter was safe with the M3 and tens of thousands of collapsible lenses it is safe with a digital M. Of Cause the sensor will be never touched because it's "far" behind the shutter: at the same place where the film for an M3 was, and it was never touched and won't be touched today. 

Rests the roller. The roller has exactly the same position since the Leica II. It was the same for any M model and still is the same today: otherwise you were not able to use older lenses coupled with the rangefinder. Yes, this roller can be touched if you collapse a lens. Though it could be touched in a Leica II as well - Barnack and Berek could live with it. It could be touched in an M3 - M7 - nobody worried about this. And now it can be touched in a digital body - and everybody speaks of big risks. We live in an age of risks which only exist because of certain liability laws and in the internet. 

Though I can only repeat: there is no real reason to collapse any lens in a digital body. The demand for collapsible lenses came from a time when people wanted to carry their cameras in a vest pocket or in very flat leather bags. Those bags have gone, and there are many other reasons that a diital camera won't be comfortable in a vest pocket. So leave the tube extracted. If you store your lens with a rear cap it has to be extracted anyway. The lenses mechanics will thank you if you don't collapse it. 

 

Edited November 13, 2023 by UliWer

[alfisti71]

28 minutes ago, UliWer said:

I shall not propose to collapse any lens in a digital M body ...

... though any fear that this will damage the shutter or even the sensor is not justified. Please think of the M3: it originally had standard lenses which were collapsible - 50mm Elmar and Summicron, even a collapsible 90mm Elmar. There were still many Summitars in usage with the well known adapters: Did any of the lenses hit the shutter - or even the film! - of an M3? No, and nobody feared they would.

Now if you measure: which camera has a shorter distance between the flange and the two metal ridges which are immediately in front of the shutter? is it the M3 or a digital M?

I measured: the distance is considerably shorter for an M3 than for a digital M because the two ridges were much fatter.

So if the shutter was safe with the M3 and tens of thousands of collapsible lenses it is safe with a digital M. Of Cause the sensor will be never touched because it's "far" behind the shutter: at the same place where the film for an M3 was, and it was never touched and won't be touched today. 

Rests the roller. The roller has exactly the same position since the Leica II. It was the same for any M model and still is the same today: otherwise you were not able to use older lenses coupled with the rangefinder. Yes, this roller can be touched if you collapse a lens. Though it could be touched in a Leica II as well - Barnack and Berek could live with it. It could be touched in an M3 - M7 - nobody worried about this. And now it can be touched in a digital body - and everybody speaks of big risks. We live in an age of risks which only exist because of certain liability laws and in the internet. 

Though I can only repeat: there is no real reason to collapse any lens in a digital body. The demand for collapsible lenses came from a time when people wanted to carry their cameras in a vest pocket or in very flat leather bags. Those bags have gone, and there are many other reasons that a diital camera won't be comfortable in a vest pocket. So leave the tube extracted. If you store your lens with a rear cap it has to be extracted anyway. The lenses mechanics will thank you if you don't collapse it. 

 

Thanks Uli. Sounds like it is not worth the effort to retract the lens for portability. That just leaves the "what if it happens accidentally" question. In which case, it's possible the world will not stop spinning - but it sounds best to be avoided. Thanks

[dpitt]

3 hours ago, alfisti71 said:

Thanks. This sounds like a good plan. I would like to be able to mount/dismount without extending - not because I NEED to, but because I feel like I'm likely to forget to extend it at some point, and I do not want to cause any damage. It seems little shim to keep it from collapsing all the way is cheap insurance. 

Using a Dymo tape does not help much with the possible roller issue, just as @UliWer said. So the rule to always extend the lens to mount/dismount stays unless the tube only enters the body for a few mm in collapsed state. I find it hard to forget to extend the lens when dismounting since the loosely turning barrel when collapsed makes dismounting (turning the bayonet) harder.

2 hours ago, IkarusJohn said:

I have the 50/2 Summitar LTM from 1948, with the Voigtlander adapter.  With my TL2, the end of the lnes brushes against the housing inside the lens mount if I collapse it.  I have not been prepared to collapse it inside my M cameras (as the manual says not to) for fear of damaging the shutter, the roller or the sensor on the Monochrom or the M10-D.

I prefer to have a ring or thick piece of string or whatever else I find around the house tied around the tube so it doesn’t go too far in.

I see no point in taking the risk …

This is a special case. The TL2 has a rim around the sensor that is very high compared to the digital M. And because the barrel is larger than the APS-C sensor it will bump into it.

2 hours ago, UliWer said:

...

Though I can only repeat: there is no real reason to collapse any lens in a digital body. The demand for collapsible lenses came from a time when people wanted to carry their cameras in a vest pocket or in very flat leather bags. Those bags have gone, and there are many other reasons that a diital camera won't be comfortable in a vest pocket. So leave the tube extracted. If you store your lens with a rear cap it has to be extracted anyway. The lenses mechanics will thank you if you don't collapse it. 

 

Call me old fashioned, but I like to put my M9 with lens mounted in my coat pocket. And if not in the pocket, I carry a small purse, just large enough for an M with lens mounted. So, I love small lenses like the Summicron 40 C or smaller and collapsible 50 mm lenses.

I agree with you that the collapsing barrel is an extra weak point in the lens construction. OTOH Leica made them like this, and as always they made this to last for ever. So if you do it with care you can extend/collapse these lenses 100's of times. I have a nickel 5 cm Elmar that is almost 100 years old and it still slides in and out perfectly.  And when collapsed, the lens is more protected against side ways pressure and dirt. Actually, any accidental bump could bend the barrel of a collapsible lens that is extended. It would have a better chance of surviving when collapsed IMO.

Edited November 13, 2023 by dpitt

[alfisti71]

20 hours ago, dpitt said:

Using a Dymo tape does not help much with the possible roller issue, just as @UliWer said. So the rule to always extend the lens to mount/dismount stays unless the tube only enters the body for a few mm in collapsed state. I find it hard to forget to extend the lens when dismounting since the loosely turning barrel when collapsed makes dismounting (turning the bayonet) harder.

This is a special case. The TL2 has a rim around the sensor that is very high compared to the digital M. And because the barrel is larger than the APS-C sensor it will bump into it.

Call me old fashioned, but I like to put my M9 with lens mounted in my coat pocket. And if not in the pocket, I carry a small purse, just large enough for an M with lens mounted. So, I love small lenses like the Summicron 40 C or smaller and collapsible 50 mm lenses.

I agree with you that the collapsing barrel is an extra weak point in the lens construction. OTOH Leica made them like this, and as always they made this to last for ever. So if you do it with care you can extend/collapse these lenses 100's of times. I have a nickel 5 cm Elmar that is almost 100 years old and it still slides in and out perfectly.  And when collapsed, the lens is more protected against side ways pressure and dirt. Actually, any accidental bump could bend the barrel of a collapsible lens that is extended. It would have a better chance of surviving when collapsed IMO.

that is part of my concern. I'm looking at the lens extended on my M-P 240, and I'm thinking, I can't put this in my bag this way. It's going to collapse on its own in my bag. 

[dpitt]

18 minutes ago, alfisti71 said:

that is part of my concern. I'm looking at the lens extended on my M-P 240, and I'm thinking, I can't put this in my bag this way. It's going to collapse on its own in my bag. 

I challenge any member of this forum to report damage done to any digital M by collapsing the collapsible M lenses.

I have not read any report on it, and have been using them collapsed on both the M8 and M9 from time to time without issues. I have more than 5 types which have been collapsed on my digital M's at some point at least once. My Summicron 50 collapsible was practically glued to my M8 for a year. And I kept using them on M8 and M9. I even mounted and dismounted them a few times when collapsed. First, because I did not know better and afterwards a few times out of habit or by accident.

I even used my Summicron in collapsed state for a shoot 😀 . Every shot carefully focused and totally blurred
This is not advisable, and almost as bad as using it with the cap on... I suppose every user has done that by accident on occasion.

Unless someone comes with proof of damage by just collapsing a mounted lens, I would just use it. Add the Dymo tape if you feel better about it, but I would take the risk with the RF roller as users from any M since 1954 have done.

Edited November 14, 2023 by dpitt

[IkarusJohn]

Not sure if I’m brave enough!

My Summitar is LTM. Now, I accept that, when extended with the adapter, the register distance between the rear of the lens and the sensor is the same as any M lens. But the length of travel of the tube is unrelated to the register distance. 

I may be missing something, but the issue is the location of the shutter, relative to the collapsed lens. 

I guess the simplest solution is to try (?) or never collapse the lens while mounted. 

 

Edited November 14, 2023 by IkarusJohn

[dpitt]

2 hours ago, IkarusJohn said:

...

I may be missing something, but the issue is the location of the shutter, relative to the collapsed lens.
 

Look at post #4 by @UliWer about the FAQ.

It states that the position and build of the shutter in digital M camera's allows even more distance for the tube of collapsible lenses than analog M bodies. The M with the smallest distance between flange and first obstacle is the M3! And Leica has released several collapsible lenses that have been used on the M3 for decades.

Edited November 14, 2023 by dpitt

[alfisti71]

12 hours ago, dpitt said:

I challenge any member of this forum to report damage done to any digital M by collapsing the collapsible M lenses.

I have not read any report on it, and have been using them collapsed on both the M8 and M9 from time to time without issues. I have more than 5 types which have been collapsed on my digital M's at some point at least once. My Summicron 50 collapsible was practically glued to my M8 for a year. And I kept using them on M8 and M9. I even mounted and dismounted them a few times when collapsed. First, because I did not know better and afterwards a few times out of habit or by accident.

I even used my Summicron in collapsed state for a shoot 😀 . Every shot carefully focused and totally blurred
This is not advisable, and almost as bad as using it with the cap on... I suppose every user has done that by accident on occasion.

Unless someone comes with proof of damage by just collapsing a mounted lens, I would just use it. Add the Dymo tape if you feel better about it, but I would take the risk with the RF roller as users from any M since 1954 have done.

Thanks - I'm specifically concerned about my lens, which is LTM. 🙂 Might be the same situation, though!