Re-installing R bayonet lens problem: suggestions needed!

[andyedward]

Advertisement (gone after registration)

I'm having difficulty re-installing the R bayonet after removing the leitax F on my elmarit-r 100/2,8, and was wondering if anyone can suggest a solution please?

 

I had everything aligned, popped on the ball bearing+grease, lowered the R bayonet on, and tightened the screws gradually and gently. When the 10 bayonet screws are tightned to a reasonable amount (so they wont come undone, but are secure enough), the aperture ring will not rotate, yet when they are almost completely slackened off, the aperture ring works. All ten screws need to be slackened for the aperture to rotate - slackening either short or long screws independently of each other isnt enough.

 

It appears as though tightening the screws to a safe amount locks/traps the ball bearing in just one of the possible aperture detents on the underside of the bayonet (the side you cannot see when the bayonet is secured on the lens), which prevents the apeture ring from rotating.

 

AFAIK I kept all the left over parts from leitaxing it, but perhaps I'm missing something. Perhaps I have reassembled it incorrectly, but cannot see where I may have gone wrong. When I had it leitaxed, the aperture ring moved appropriately, though became slightly tight when tightened appropriately, thus requiring an occasional tightening of the screws.

 

This is a pain because I have an R9 on the way, so I dont want to lose time sending the lens off. BTW, I started another thread on getting dust removed from this lens, but since I last had a look at it a few months ago, I now cannot see the large spec which had been problematic (perhaps my standards have slipped!), so I wasnt planning on having it serviced.

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[mmradman]

Andy,

 

In my experience common issue whether leitaxing or reversing R lenses, probable misalignment.

 

I use longish sawing needle as an alignment guide - about 3" and make sure it doesn't drop inside the lens. Once flange is aligned with the lens and little ball & spring greased and in place check that aperture is operating correctly - both ring and blades. Once satisfied tighten either 6 or 10 screws - depending on lens. For a good measure keep guide needle in place unit you have fitted at least 2 screws although one is enough.

[AB007]

The 100/2.8 APO was a tough lens for me to Leitax. I had Leitaxed 3 R lens earlier without any problems. It was very easy when I converted my 50/2, 90/2.8 and 180/3.4 APO. Maybe my overconfidence got me there.

 

Finally, I sent it to DAG who fixed it for me. He asked me if I wanted it Leitaxed. I decided not to and been using it on my R bodies.

 

I use my Leitaxed 2x APO to use my 100/2.8 APO on Nikon DSLRs.

[andyedward]

Andy,

 

In my experience common issue whether leitaxing or reversing R lenses, probable misalignment.

 

I use longish sawing needle as an alignment guide - about 3" and make sure it doesn't drop inside the lens. Once flange is aligned with the lens and little ball & spring greased and in place check that aperture is operating correctly - both ring and blades. Once satisfied tighten either 6 or 10 screws - depending on lens. For a good measure keep guide needle in place unit you have fitted at least 2 screws although one is enough.

 

Mladen, Many Thanks for your reply. I did as you suggested by using wide, blunt sewing needles as guides. I aligned the 10 holes of the body with the depth of field scale, placed the guides down opposite long holes, then aligned and slid the R bayonet over the guides. I then added the other screws, then removed the guides. Same result, I'm afraid. It's a mystery.

 

The 16 aperture click stops on the 100/2,8 are on the underside surface of the bayonet, and are concave. On my 100/2,8, tightening the screws prevents the ball bearing from moving from one concave click stop to the next, so the aperture ring wont move

[S. Wong]

I'm looking at the instructions provided on letiax's site, APO-MACRO Elmarit 100/2.8, and it looks to me like the 10 screw bayonet mount is symmetrical with regard to the screws.

 

From the photos, it looks like there are detentes in the mount, so you should hear and feel positive clickstops, which I'm assuming you do.

 

If you don't feel & hear clickstops, the mount may be installed upside-down.

 

In addition, looking at the leitax site, there are a strange pattern to long & short screws with the mount. I'm assuming you've put those in in the correct holes.

 

Also, perhaps you spring got stretched?

Maybe its pushing the ball to far up?

 

Doug Herr (wildlightphoto) would be a good resource for mount problems, he's done a lot of work with them.

 

Good Luck!

[jaapv]

I would leave it and send the lens to Will van Manen.

[andyedward]

Advertisement (gone after registration)

No luck yet, but I have found out how to remove the rear elements housing.....

 

1. Remove the bayonet

 

2. Remove the aperture by easing it off

 

3. Holding the part of the lens body inside where the aperture ring sat, gently slide it away from the main body of the lens. The rear element is attached to it.

 

To re-assemble, the rear element housing has "female" guide into which the "male" guide of the main body slots, but care is needed to do this accurately.

 

I gave the internal element surfaces a clean with the rocket blower and stuck the rear element housing back in.

 

From this I found that the short bayonet screws tighten in the rear element housing, whilst the long screws pass through the rear element housing, and tighten in the part of the body below the rear element housing.

The rear element is a deep piece of glass with a concave internal surface, and its appearance reminded me of the engineering drawing in leicas PDF document for this lens.

 

It appears this lens is easier to dissasemble than re-assemble correctly [no sh*t!!!]. Resolving this is above my level of skill and knowledge, so the lens is going to my local dealer on monday

[naturephoto1]

No luck yet, but I have found out how to remove the rear elements housing.....

 

1. Remove the bayonet

 

2. Remove the aperture by easing it off

 

3. Holding the part of the lens body inside where the aperture ring sat, gently slide it away from the main body of the lens. The rear element is attached to it.

 

To re-assemble, the rear element housing has "female" guide into which the "male" guide of the main body slots, but care is needed to do this accurately.

 

I gave the internal element surfaces a clean with the rocket blower and stuck the rear element housing back in.

 

From this I found that the short bayonet screws tighten in the rear element housing, whilst the long screws pass through the rear element housing, and tighten in the part of the body below the rear element housing.

The rear element is a deep piece of glass with a concave internal surface, and its appearance reminded me of the engineering drawing in leicas PDF document for this lens.

 

It appears this lens is easier to dissasemble than re-assemble correctly [no sh*t!!!]. Resolving this is above my level of skill and knowledge, so the lens is going to my local dealer on monday

 

I just hope that whoever does the work can get all of the optical elements aligned properly for best performance. That is why I take (or would ship) any of my Leica lenses to Leica USA because they align everything and do all and any work to return the lens to factory specs.

 

Rich

[andyedward]

I managed to get the aperture ring working, but without the spring and ball bearing, so there are no click stops. I think the spring had lost its spring, so I'll try to find a new one. The aperture ring is damped enough.