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Our Simmod CINE OFFSET Aperture Gear for Contax Zeiss lenses is designed with precision and functionality in mind.  The Cine Offset Gear extends the position of the aperture ring away from the mount by 5mm, providing clearance and allowing SIMple aperture controls either by finger or a motor without interfering with the mount.  It's perfect for those with large fingers--and users who wish to install an aperture motor without fear of hitting the mount.


The Cine Offset Aperture Gear is held onto the native aperture ring by the 5 included set screws. Also included in the kit is a key tool.


Installation is SIMple:


1: Remove the native rubber grip on the aperture ring.  Remove ONLY the rubber grip, not the entire aperture movement.


2: Install the set set screws on the Cine Offset Gear.


3: Slide the Cine Offset Gear on the aperture ring.


4: Tighten the set screws.  Do not over-tighten the screws.  Overtightening will cause the aperture control to seize.  If this happens, loosen each set screw incrementally.


Simmod Seamless Aperture Gears are machined from solid aluminum and anodized in black.  Each gear is 0.8-module  and designed for compatibility with all industry-standard motors and focusing units.  


Installation is SIMple with the supplied 5 set screws and key.  These gears are measured to fit only Zeiss Contax / Contax Yashica lenses.




  • 0.8-module
  • 4mm width
  • 7.5mm height
  • 83mm Outer Diameter
  • Anodized Aluminum
  • 6 set screws

Contax Zeiss Aperture Gears - CINE OFFSET


    ***Please allow 3-5 business days for engraving***


    Do you have a custom design or logo you'd like on your caps? Send it to with your order number in the subject line.


    Special Instructions:

    • Requests to change lens information and data will not be accepted once an order is submitted for processing and engraving.

    • Please leave notes and instructions for EACH cap in the "Additional Info" Section. 

    • If you're sending us a custom design file, please let us know by selecting the corresponding options or simply indicate that in your instructions.

    • If you do not see your focal length or f.stop in the pull-down menu, DO NOT select the closest number.  Please leave the exact info in the "Additional Info"  Section

    • If you will be submitting a custom design file, please note that on the order.

    • For custom designs, please download this Illustrator TEMPLATE and export as a transparent (no background) PNG file.  Email the design file to with your order number in the subject line.


    Watch Mark Holtze's video to learn more about the SIMMODING process: VINTAGE LENSES FOR VIDEO


    Our Rear EF caps utilize a 1mm thick anodized aluminum top plate, allowing us to custom engrave to your specifications. Functional and stylish.


    Want a matching Engraved Front Cap? Check them out here!


    If you do not see a brand or focal length you are looking for, simply select OTHER and leave us a note.

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