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marknorton

Is it safe to collapse a 50mm Elmar?

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This is a question which has been asked several times before. Warnings in the Leica manual seem to advise against it, others (myself included) report no problems.

 

While I was finishing off the FF Mock-Up, I had the idea of mounting this lens to show you using my last generation Elmar with the M8.

 

The good news is that, when collapsed (and at infinity focus), the lens barrel does not come up above the edge of the lens throat and there is no risk of it damaging the shutter.

 

 

 

However, the clearance between the edge of the lens barrel and the floor of the lens throat is tiny, less than 1mm and I expect it would be possible to damage the internal flocking of the lens throat if the lens was inserted at an angle, retracted, into the camera. It might of course be possible to touch-up any damage with matt/flat black paint, but replacing the lens throat calls for major, major surgery.

 

 

 

So, the best advice I can give is:

 

- Mount and remove the lens with the barrel extended

 

- Only retract the lens once it is mounted.

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What happens if the lens is collapsed and it isn't focused at infinity?

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Thanks, Mark. Very interesting. Do you happen to have any other collapsible lenses to try?

 

Alternatively, what's the diameter across the bayonet flanges at the back of the 50/2.8 Elmar-M? On the screw-mount 50/2.8 Elmar the barrel is about 29.0 mm and the flanges take it up to about 30.4mm.

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Ruben, having the lens focussed at infinity is the worst case; if the lens is focussed closer, it moves away from the focal plane, so the intrusion into the lens throat is less.

 

John, good point, I'll measure my lens. The collapsible 90mm Elmar is of course not a problem.

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Ruben, having the lens focussed at infinity is the worst case; if the lens is focussed closer, it moves away from the focal plane, so the intrusion into the lens throat is less.

 

John, good point, I'll measure my lens. The collapsible 90mm Elmar is of course not a problem.

 

The current Elmar 90 isn't a problem, but the old collapsible one might be. Unfortunately I don't have one to measure.

 

IIRC the old f/2.8 Elmar had the same barrel diameter and bayonet as the Summitar and collapsible Summicron (maybe also Summar and Hektor) so they could all be used on the various close-up devices. The f/2 lenses don't retract as far as the Elmar because of their rectilinear mounts, but the Hektor retracts further and is the one most likely to foul the shutter.

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No, it's the original Anatomy M8, waiting to be put together after I worked on my own delayed shutter wind which, of course, was then not needed because it was made generally available.

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I am happy to see Mark confirm my advice: Mount or remove collapsible 50mm Elmar lenses, of any vintage, extended only. Collapse ad libitum when on the camera.

 

What about LTM lenses in M bayonet rings?

 

The old man from the Age of the Leica IIIa

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I've measured my 50mm Elmar and, retracted, the end of the lens tube is 20.76 behind the bayonet ring. The diameter from the outer edge of one of the three flanges across to the opposite edge of the lens tube is 30.25mm. Anything smaller and you are fine; if your lens is larger diameter especially, don't collapse it.

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On the collapsible 50 Summicron, there are three lugs that stick out a little from a rim that has a 28.9 mm diameter. Each lug is another 0.9 mm, so I think the overall diameter at the back is 30.7mm. But it protrudes only about 1 cm into the lens cavity.

 

scott

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I've measured my 50mm Elmar and, retracted, the end of the lens tube is 20.76 behind the bayonet ring. The diameter from the outer edge of one of the three flanges across to the opposite edge of the lens tube is 30.25mm. Anything smaller and you are fine; if your lens is larger diameter especially, don't collapse it.

 

Fabulous definitive confirmation.

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I don't have elmar to test it but...

however...Exellent... great descriptions and pictures ^^

Edited by David M.

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Hi Mark & Everyone,

 

Although I haven't heard of there being any problem, is it completely safe to to mount (whether first colapsed or not set at "infinity" or any focusing disatnce) the current Leica 90mm f4 Macro-Elmar M lens (6 bit)? One individual told me like some of the older collapsables, it might be an issue. Thanks for any insight.

 

Dave (D&A)

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Hi Mark & Everyone,

 

Although I haven't heard of there being any problem, is it completely safe to to mount (whether first colapsed or not set at "infinity" or any focusing disatnce) the current Leica 90mm f4 Macro-Elmar M lens (6 bit)? One individual told me like some of the older collapsables, it might be an issue. Thanks for any insight.

 

No insight needed. Your individual had not consulted the instruction book.

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Great info. Thanks Mark and all.

 

The Hexanon LTM 50/2.4 with adapter extends beyond a 124xxxx coll. cron by a mm or so, but less than Elmars.

 

I like to set my lenses on min. focus before collapsing, just to leave an extra mm or so away from sensor and shutter, and always attach and remove in extended mode.

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Great info. Thanks Mark and all.

 

The Hexanon LTM 50/2.4 with adapter extends beyond a 124xxxx coll. cron by a mm or so, but less than Elmars.

 

I like to set my lenses on min. focus before collapsing, just to leave an extra mm or so away from sensor and shutter, and always attach and remove in extended mode.

 

This is good to know. Does anyone know whether the M240 has the same throat dimensions?

 

Thanks

Dante

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I have mounted the same lens - last generation 50mm Elmar - on my M240 and there are no problems but my advice remains the same - mount it with the lens extended and retract only when the lens is mounted.

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...One individual told me like some of the older collapsables, it might be an issue...

 

Never try to collapse an old Elmar 4.0 - 90 mm on digital Leica-Ms.

It will ruin the sensor with its long tube.

 

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