Canon Mount Adapter EF-EOS R 0.71x

Full-frame field of view with EF lenses on Super 35

The Canon Mount Adapter EF-EOS R 0.71x is an optical EF-to-RF adapter developed primarily for the EOS C70. It allows compatible full-frame Canon EF lenses to be used on the camera’s Super 35 sensor while maintaining an angle of view similar to the same lens used on a full-frame camera. The 0.71x optical reduction concentrates the lens image onto the smaller sensor area, making wide-angle EF lenses much more useful on Super 35 productions.

One-stop increase in lens speed

A major advantage of this design is the one-stop increase in light transmission. In practical terms, an EF lens with a maximum aperture of f/2.8 delivers brightness comparable to approximately f/2.0 after the optical reduction. This can be especially valuable for low-light work, interiors and productions where keeping ISO lower is important. The adapter therefore changes both the effective field of view and the amount of light reaching the sensor, rather than simply acting as a mechanical mount converter.

Electronic communication and compatible lens functions

With supported EF lenses, the adapter maintains electronic communication between lens and camera. Canon specifies support for Dual Pixel CMOS AF, Auto Exposure, Auto Iris and lens metadata, including accurate recording of focal length and aperture information. Compatible combinations can also use camera corrections for vignetting and lateral chromatic aberration. Because full functionality depends on the exact lens and adapter firmware, checking Canon’s current compatibility list is recommended before a shoot where autofocus or electronic lens control is critical.

A practical option for Canon cinema setups

For EOS C70 users, the adapter is particularly useful when a production already relies on professional EF photography or cinema lenses and wants a field of view closer to their full-frame character. Canon secures the unit to the C70 with four additional screws alongside the RF mount, creating a more rigid connection for production use. Our rental set includes the Canon optical adapter, original front and rear caps and a carrying case for transport and storage.

Rent Canon Mount Adapter EF-EOS R 0.71x at CamCam Rental

At CamCam you can check current availability online and reserve the adapter together with compatible Canon cameras, EF lenses and rigging accessories. If you are unsure whether a specific lens will provide full electronic functionality, our team can help you choose and test a suitable combination before your production. We also offer delivery and collection, optional on-set assistant support, after-hours returns, free parking and free equipment tests by arrangement. CamCam is open seven days a week, including weekends.