Thread: Zeiss Contax with Cine Mod - back of lens metal issue

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  1. #1 Zeiss Contax with Cine Mod - back of lens metal issue 
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    Hey All,

    I recently finished the Cine Mod through Duclos Lenses (dampened, de-clicked, Leitax EF mount conversion, etc.) for my set of Zeiss Contax. They're awesome, but I've noticed an issue that I've read others talking of on this forum, as well as others.

    Was trying them out on a GH5 with a Metabones SB Ultra... I did some searching, and I'm pretty sure I'm seeing some issues with the aperture not behaving correctly. It freezes when I stop down, and depending on the lens, I lose a stop or sometimes several, where the blades just won't respond after a certain point. I want to say it was the worst on the 35mm. From what I can tell this happens to the AEG's, not the MM's (I have the 21 mmj).

    When I take the lenses off, the aperture blades respond perfectly when adjusting.

    After reading different forums I’m seeing a lot of info about the aperture lever and pieces of metal on the back of the lens. People are having to shave them down for the lenses to work correctly on the speedboosters (so they won't damage SB and get stuck on the pins, metal, etc). Assuming that’s correct is the focus lever then, and that other piece of metal sticking out, useless for lens operation on digital cameras? Why are they there in the first place. For C/Y mount cameras?

    Has anyone shaved these down at Duclos or anywhere else? Does it work? Damage the lens, etc.? Does this issue exist only with the Speedboosters?

    Thanks in advance for any info.
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  2. #2  
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    Yeah since the contax lenses have no electronic connection in them then the only way for the iris to 'freeze' it's that it's actually stuck. The protruding lever moves as you change the iris and it's most likely contacting your speedboosters lens pins. Shaving them off will work as they were only intended to be used on cameras that connected with that lever. Continuing to use them may cause damage to the speedbooster.

    Best to let a professional deal with the shaving but I have seen people use a dremel to shave and cover up the optics so metal shavings don't get in.
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  3. #3  
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    Hey Ryanite,

    Thanks for the info.

    I've contacted Duclos and they said they can do it.. I definitely won't try haha.. I could see things going very wrong with that.
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  4. #4  
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    140 bucks right, more with shipping? Just get some end-cutters or dykes and nip it off, better yet just remove it through disassembly. Easy breezy, Dremel is the wrong tool, makes a mess for no reason, the metal is soft and easily cut with the proper tool.

    Good Luck
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  5. #5  
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    Hey Howie,

    Have you done that with the cutters? The only worry I had was if I'm cutting into it, keeping the lens itself stable so I'm not putting damaging force on the aperture controls inside the lens, through the cutting motion that is.

    If I could ensure not screwing up anything inside the lens, then I'd be fine with saving the cash and time to get the lenses back up there.
    Last edited by sohara24; 06-27-2018 at 01:18 PM.
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  6. #6  
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    This is an end-cutter, you can also use dykes, the lever material is soft. There is no cutting motion, just a quick nip.

    I've done it, super clean and easy. Still it's better to disassemble and remove the lever.

    xtl-0050__1_3.jpg
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  7. #7  
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    Hey howie, do you only need to remove the Iris lever or the little ribbed part that peotudes also?
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  8. #8  
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    They are all a little different. I had to remove the lever and maybe the fin to get my Leitax mount on the lens, it might have been the 50 or the 35. It's all a little soft, that was 10 years and a few lens sets ago.
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