FREE JIS Screwdriver included with every order (1 per order)


Say goodbye to cheap, flimsy adapters and say hello to the SIMMOUNT EF Conversion Kit! 


Designed for precision, functionality, and durability, our EF Conversion kits will allow you to make the most out of your existing collection of Contax Zeiss lenses.  The SIMMOUNT System allows you to mount native Contax Zeiss lenses to any Canon EF/EF-S-mount camera or EF mounted motion picture camera.  State of the art CNC construction ensures a tight fit, while maintaining infinity focus and proper functionality between camera and lens. 


The SIMMOUNT System is made of high quality air craft grade aluminum, anodized in matte black to reduce glare and reflections, and backed by a lifetime replacement warranty.


Please note that in order to make Contax Zeiss lenses compatible with Metabones Speedboosters, you must remove the rear protruding pins on your lens.  We offer a service for this removal.  Damage can be casued to your Speedbooster if not removed.


Installation is as simple as 1-2-3:



1:  To avoid stripping the screws, we strongly recommend using a soldering iron to apply heat to each screw before removing them.  Make sure you use the proper JIS  size screwdriver.  We are not responsible for stripped screws.


Hold the soldering iron on each screw for 5-8 minutes to dissolve the glue applied to the screw from the factory.  Remove the screws.


2:  Once the screws are removed, simply place the SIMMOUNT directly on top of the native mount.  Make sure the SIMMOUNT logo aligns to the top of the lens and all the screw holes are matched.


3:  Use the ORIGINAL screws to tighten down the SIMMOUNT.  Do not overtighten.


***If you do not see your lens in the drop down menu, please select OTHER and leave a note upon checkout.  We are working on fixing the number of lenses we can list***



    ***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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