Today Only: Save 20% On Metabones EF to RF Mount T Speed Booster ULTRA 0.71x – $383 (reg. $479)

Metabones Rf To Ef

Only for today (2/6/2023) both B&H Photo and Adorama have a 20% discount (that’s $96) on the Metabones EF to RF Mount Speed Booster ULTRA 0.71x adapter.

At a glance:

  • Canon EF Lens to Canon RF Body
  • Full-Frame Lens to RF Camera Body
  • For UHD 4K Video Capture
  • 0.71x UHD 4K Crop Factor Compensation
  • 1-Stop Increase in Lens Apertures
  • Supports In-Camera Aperture Control
  • Transfers Lens EXIF Metadata to Camera
  • Anti-Reflective Matte Black Interior
  • Removable, Arca-Type Tripod Foot
  • 1/4″-20 Tripod Foot Accessory Threads

Get the Metabones T Speed Booster Ultra 0.71x Adapter for Canon Full-Frame EF-Mount Lens to Canon RF-Mount on sale at $383: B&H Photo and Adorama.

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Canon Mount Adapter EF-EOS R 0.71x Speedbooster Explained

EF-EOS R 0.71x

Here is a short video introducing the new Canon Mount Adapter EF-EOS R 0.71x, a speedbooster-like adpater to mount EF lenses on RF mount cameras. The Mount Adapter EF-EOS R 0.71x was announced along with the Canon EOS C70.

From Canon:

This adapter converts light transmission from full-frame to Super 35mm image format. It extends the angle of view and optical sensitivity, while seamlessly integrating with the camera’s optical corrections. mount adapter.

In addition to the flanges of the RF mount, four screws securely attach the adapter to the camera. Once mounted, the adapter maintains a similar angle of view of your full frame lenses on the Super 35mm sensor, while boosting the speed of the attached lens by an average of 1-stop. The adapter also carries all EF information through to the RF contacts, so on certain lenses, full DPAF and metadata will be available, working much as they do on a native EF mount.

Canon Will Announce An EF-EOS R 0.71x Speedbooster


Along with the leaked press release for the Canon EOS C70, there is another interesting information.

Canon will release their first speedbooster-like 0.71x adapter to mount EF lenses on EOS R bodies. It was rumored and a patent showed up too.

From the press release:

Also launching today is the Canon Mount Adapter EF-EOS R 0.71x – an EF Lens to RF Mount adapter giving filmmakers the freedom to use the entire EF lens line-up1 with the EOS C70, optimising compatibility across two of Canon’s most popular lens lines. When paired with the EOS C70, the Mount Adapter EF-EOS R 0.71x employs an optical conversion to capture a Full Frame angle of view of an EF lens even when used with a Super 35mm sensor, as well as an increased light transmission of approximately 1-stop. The adapter enables full communication between three EF lenses and the camera body – EF 16-35mm f/2.8L III USM, EF 24-70mm f/2.8L II USM, and EF 24-105mm f/4L IS II USM- providing continued support for Canon’s extensive range of EF lenses2. Auto Focus, peripheral illumination and chromatic aberration correction, and the transfer of lens metadata are also fully supported when using the Mount Adapter EF-EOS R 0.71x

Canon Might Release A Speedbooster And New Adapters For RF Mount


Canon might soon announce new adapters for the RF mount, i.e. the mount of the company’s EOS R full frame mirrorless camera system. And a Speedbooster might also get announced.

Rumor has it that Canon might release some interesting adapters for the RF mount, all of them likely within 2020.

  • PL to RF with Cooke/i
  • EF-Cinema Lock to RF
  • Speedbooster

That Canon was working on their own speed booster was in the air. A pertinent patent was spotted time ago. For those who want to learn what a Speedbooster is, have a look here.

A Canon announcement in August or September 2020 is already rumored. The adapters might get announced along with new Canon EOS M cameras and a new EOS R camera.

Stay tuned, and don’t forget to snap pics.

Source: Canon Rumors

Metabones Release EF-RF Speed Booster That Reduces EOS R 4K Crop Factor


Metabones released a new Speed Booster for the EOS R system.

The Canon EF-RF mount T Speed Booster® ULTRA 0.71x is able to able “to mitigate most of the 4k video crop factor of EOS R (1.75x) and EOS RP (1.63x) and reduce it to 1.24x and 1.15x respectively“.

The Metabones Canon EF-RF mount T Speed Booster® ULTRA 0.71x is already available for $479 at B&H Photo | Adorama | Metabones

Key Features

Metabones EF-RF Speed Booster®  ULTRA 0.71x – to adapt Canon EF mount full-frame lenses to the new Canon RF mount. Filmmakers are now able to mitigate most of the 4k video crop factor of EOS R (1.75x) and EOS RP (1.63x) and reduce it to 1.24x and 1.15x respectively. The field of view is now much closer to still photo mode. This Speed Booster is not intended for still photography but will work if the camera is configured to APS-C mode. 60p FHD video does not work at all.


  • Increase maximum aperture by 1 stop. (with a maximum output aperture of f/0.9).
  • Increase MTF (details).
  • Makes lens 0.71x wider.
  • Advanced 5-element/4-group optical design incorporating ultra-high index tantalum-based optical glass by Caldwell Photographic in the USA (patent granted).


  • Autofocus.  AF speed is properly adjusted to account for and leverage the shorter focal length and the brighter maximum aperture.
  • Dual-pixel autofocus (DPAF) and video AF support.
  • Focal length and aperture are adjusted in EXIF (see note 3).
  • Image stabilization (IS) lens support.
  • Store EXIF data (lens name, focal length and maximum/minimum aperture) for one manual lens in the adapter.
  • Build-in multi-function Control Wheel (turn/ push-in) for assignable functions(eg. ISO, shutter speed or aperture control, depth-of-field preview).
  • LED indicator shows communication status. 
  • Powered by camera body. With most lenses, no external power source required.


  • The tripod foot is detachable and compatible with Arca Swiss, Markins and Photo Clam ball heads.
  • Flocking to reduce internal reflection.
  • Rubber gasket protects the RF mount connection from dust and moisture.
  • Aluminum alloy and brass construction with chromium plating.
  • Satin surface finish.
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Metabones Announced EF to EOS M Speed Booster ULTRA 7.1x

Speed Booster

Metabones announced a new Speed Booster (EF to EF-M mount). Metabones EF-EOS M Speed Booster ULTRA 0.71x is available right now for $479.

Press release:

Metabones® Introduces EF to EOS M (EF-EFM Mount) Speed Booster® ULTRA 0.71x

Vancouver, Canada, May 2, 2019 – Metabones introduces the latest member of its award-winning Speed Booster family of DSLR (digital single-lens reflex) to mirrorless lens mount adapters, EF-EOS M Speed Booster ULTRA 0.71x. Full-frame Canon EF-mount lenses are now one stop faster, 0.71x wider and with increased MFT (note 1) on Canon EOS M cameras. The 4k/UHD video crop on EOS M50 can also be mitigated with third-party APS-C lenses using this Metabones Speed Booster. Some Canon EF-S lenses may be modified to fit on the Speed Booster but Metabones cannot be held liable for any issues arising from modifications. Using APS-C lenses with Speed Booster for still photography or full HD videography may result in vignetting.

Ever since the first Speed Booster was introduced, there have been DIY attempts to modify it to fit EOS M cameras. The turnkey solution Metabones now offers adds a number of refinements:

  • The optical housing is redesigned for perfect fit on EOS M.
  • The EXIF metadata is changed to reflect the faster aperture (note 2) and shorter focal length.
  •  The autofocus speed of the lens is adjusted and optimized for the change in focal length and aperture to ensure the best performance. This is especially important for dual-pixel autofocus (DPAF) in video mode.
  • A ‘chip’ mode is added so that the user may store the metadata of a fully mechanical manual lens in the adapter.
  • A LED indicates operational status of the Speed Booster.

Since both the lens and the camera speak the same protocol most features are supported with the exception of lens aberration correction, which is automatically turned off.

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