Is there a back to back M lens coupler without the hole?

[gary_lagnese]

I have bith M and R lens couplers. They are grey in color. The M ones are open. The R ones are closed.I prefer the closed ones because they keep the dust ot when the other lens is removed. They dont say leica onb them. If these arent leica items, are the leica ones closed or open?

[Bill Blackwell Images]

No. The M couplers are all open. Just use a body cap to cover the hole when the other lens is in use.

[charles barcellona www.bl]

Get two rear caps from Eagle (on the 'bay) and epoxy them together.

[ronald_wills]

Gary, you're right, the R-couplers are closed and the M-couplers are open to

let in dirt. I just use two rear M-caps epoxied together.

[gary_lagnese]

Thanks. Just wasnt sure if I had the authentic item. Odd that they did it this way.

[kens]

The reason the R-couplers are solid and M-couplers have a hole, is due to the difference between the demands of R and M rear lens design.

 

With the R, the lens has to clear the mirror. Thus there is minimum protrusion of R lenses into the mirror box, and R mount lenses can fit into a closed R-coupler.

 

With the M, some of the very wide lenses protrude way into the throat of the camera, right up to the film plane. There's no mirror to clear. To accomodate the variety of rear lens designs the M coupler has a hole. The idea is that you can back-to-back couple a wide lens (protruding rear element) with a normal or long lens (sunken rear element). HOWEVER...some such combinations don't work well and the lenses can damage each other. So you have to be careful when coupling M lenses. As was already suggested, I usually use a body cap to close the open hole of a coupler when necessary.

 

None of the recent Leica couplers say Leica on them. Some people buy Hexar rear caps and cement them together. As long as you cement carefully and they don't fall apart on you, it's an inexpensive way to go. I don't trust the cement so I spend the extra bucks for the Leica couplers. In the bigger scheme of Leica ownership, how much are we really talking about anyway. ;-)

[harry_soletsky1]

I use regularly the latest Leica lens caps (or the ones Stephan Gandy sells). I first sand down the back lips to make them flush with the rest of the cap and then glue them together using Elmers Pro Bond. They have worked fine for years. I have the lens couplers but as noted they are not deep enough for some lenses. I don't have a real solution for the lenses with very short back focus such as the Super Angulon except years ago, I bought one made I don't know where which had the older style Leica back caps which were Completely hallowed out and a plastic extension put in place. However, the lugs for the bayonet have become worn.