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Thread: successful conversion to sony of leica and contax lenses

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    successful conversion to sony of leica and contax lenses

    The leica conversion is via a leica adapter from I_source-global_store. Their leica adapters come with a ledge on which the chip can be easily and accurately mounted. The chip comes from big_is where it is mounted on an M42 adapter from which it must be removed. Their chips have adjustable aperture and can be custom set by them to the desired focal length.

    The Zeiss conversion is from a Pentax-Leica adapter for macro only (no glass and no infinity focus) but with a chip that is not adjustable. On the sony end of the adapter inside the flange is a flat ribbed surface. That surface is bored about to the edge of the ribs to the same diameter as the contax bayonet it must replace. The flange is then cut of the body just below the chip and fitted to the bayonet bus on the contax lens. Because the sony camera has protrusions that need to move inside the diameter of the blades while the lens is being mounted the new bayonet cannot be mounted with the indexing line for aperture adjustment at 12:00 as it is on the Contax. It can be rotated to about 10:30 o'clock and everything will work fine. Be sure you have the original bayonet fit correctly before drilling the holes. There are extra holes in the bus that can be confusing but only the correct holes will allow the screws to go all the way in.

    The leica focused to infinity without adjustment as the adapter was correct out of the box. The contax lens needed some shimming. The contax can be controlled in thickness when slicing it off the original converter. There is lots of meat on the finished adapter to adjust.

    The biggest advantage to doing the contax adapter this way is that the only things that need to be done on the contax lens is for the aperture adjustment levers be trimmed off and the bayonet removed. There is no need to open up the lens any further than taking off the bayonet.

    Here's a picture of the converter before and after: http://www.pbase.com/masimo/image/122897748/large.jpg

    The gallery below shows sample shots from a leica kyocera 35-70mm f4 zoom and a contax 28-85mm f3.3-f22 lens converted to sony mount. All exif data will say whatever the particular chipped adapters are set to. The actual titles of the pics indicate aperture and focal length.

    Gallery is here: http://www.pbase.com/masimo/leica_co...verted_to_sony

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    Re: successful conversion to sony of leica and contax lenses

    Nice work, Mike! I take it that you had no issues with the aperture ring binding against the mount? That was the main holdup on my conversion, after I took out the amateurish shims. Of course, mine was already converted poorly so for a number of reasons I think it's best I forge ahead on my slightly divergent path.
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    Re: successful conversion to sony of leica and contax lenses

    Quote Originally Posted by Dave_Anderson View Post
    Nice work, Mike! I take it that you had no issues with the aperture ring binding against the mount? That was the main holdup on my conversion, after I took out the amateurish shims. Of course, mine was already converted poorly so for a number of reasons I think it's best I forge ahead on my slightly divergent path.
    Dave,

    No problems with the aperture ring at all since it is below the bus on which the bayonet mounts. The replacement bayonet goes on the same way the original does. The only mods to the lens were to snip the aperture lever and the auto aperture levers at a level below the bus.

    Best,

    Mike

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    Re: successful conversion to sony of leica and contax lenses

    Thanks for posting. I have been considering converting my R glass to Sony mount using the Leitax conversion, but this seems to be more straight forward. Do the lens mount tightly? Is there any play between either the adapter and lens or adapter and camera?
    Thanks,
    Alan

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    Re: successful conversion to sony of leica and contax lenses

    On the leica converter there is no play and on all three lenses on which I have used the converter, a 180mm f3.4, an 80-200mm f4 and the f4 35-70mm infinity was perfect without further adjustment.

    I've only used one sample of the converter though and I may have just been lucky. I have two more on the way. Note you have to order a chip separately either by getting a chip without a converter or by getting another converter and removing the chip.

    I'm not sure how it compares to the leitax. You do have to take off the original flange and watch out for the ball bearing as there is no spare provided. But the adapter fits right back on just as the original did and the bearing mechanism works just fine.

    Mike

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    Re: successful conversion to sony of leica and contax lenses

    Sounds great. Just to make sure, is this a replacement flange like the Leitax or an adapter?
    Thanks again,
    Alan

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    Re: successful conversion to sony of leica and contax lenses

    This may seem like a silly question but what is the advantage of this over this over the Leitax mount? It seems far more complex/involved than simply unscrewing one mount and screwing on another.

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    Re: successful conversion to sony of leica and contax lenses

    Quote Originally Posted by Bill_Green View Post
    This may seem like a silly question but what is the advantage of this over this over the Leitax mount? It seems far more complex/involved than simply unscrewing one mount and screwing on another.
    Hi Bill, maybe the Leitax is easier at this point but I started this project and search before the leitax mount was available. Moreover if what I made were available without the machine work it would be a much simpler solution than the Leitax. When I saw the Leitax and saw the need to replace the aperture ring inside the mount that was an area I wanted to avoid having gone through it in the past. The contax aperture mechanism is not nearly as well engineered as the leica in my experience and it just seemed sort of silly to go through all that when a simple blade replacement would be much easier.

    I hope some enterprising Chinese entrepreneur will see the simpler solution I've created and provide it. I've done the work of finding the pieces necessary and shown how easily the conversion can be done but all development requires hard work before the end user ever sees the simplicity of the finished product.

    Mike

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    Re: successful conversion to sony of leica and contax lenses

    I think I'm understanding. Basically the Leica -> Sony conversion is pretty simple but Contax -> Sony is more involved?

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    Re: successful conversion to sony of leica and contax lenses

    Quote Originally Posted by Bill_Green View Post
    I think I'm understanding. Basically the Leica -> Sony conversion is pretty simple but Contax -> Sony is more involved?
    Yes. The leicas I've seen have all been the same, remove some screws, sometimes another piece or two. Lay the ball back in the flange with a little grease and put it back together again.

    Contax internals are similar but not as similar as the leicas are to one another. Moreover going into the contax aperture mechanism the ball is looser and so is the spring in which it rides. Both of these are much more easily lost and much less easily reassembled than on the leica.

    All that said I might have gone for the leitax for the contax had it been available when I started working on these lenses. Once I got going the leitax never really seemed like a "better" option than what I was doing.

    I also sort of enjoy this kind of stuff. I'm not good at it, just don't have the dexterity or the patience but it's still fun and interesting.

    Mike

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