• 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.

Optical

• 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).

Electronic

• 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.

Mechanical

• 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.

Sharper corners, less distortion, reduced vignetting

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 new Speed Booster is not intended for still photography but will work if the camera is configured to APS-C mode.

Speed Booster ULTRA uses an advanced 5-element/4-group optical design by Caldwell Photographic Inc., incorporating ultra-high index tantalum-based optical glass to achieve extraordinary optical performance with improved corner sharpness, distortion and reduced vignetting. Speed Booster ULTRA has a magnification of 0.71x,  effectively reducing the crop factor of 4k video on EOS R and EOS RP from 1.75x to 1.24x. The Speed Booster ULTRA design makes very effective use of exotic materials at the furthest limit of glassmaking technology, and as a result is well corrected for use with virtually all full-frame SLR lenses regardless of exit pupil distance. Thus, the Speed Booster ULTRA performs extremely well with professional-grade f/2.8 zoom lenses such as the 24-70mm f/2.8 and 70-200mm f/2.8 zooms by Canon to produce 17-50mm f/2.0 and 50-142mm f/2.0 high-speed zooms, respectively. Similarly, high-speed fixed focal length lenses such as a 50mm f/1.2 will be transformed into a 35.5mm f/0.9 lens with excellent contrast and resolution from the center all the way to the edges of the image. (More information can be found in the press release here)

Metabones Canon EF Lens to Canon RF Mount T Speed Booster® ULTRA 0.71x

Note :

• 1. EF-S lenses do not fit on Speed Booster^®. Some EF-S lenses may be modified to fit, but do so at your own risk.
• 2. EF-S lenses and third-party lenses designed for APS-C format DO NOT WORK AT ALL when used in conjunction with Speed Booster^® due to the limitation of image coverage.
• 3. For use with fast lenses (faster than f/1.4), the pre-boost apertures will be displayed in the camera.

Slow lenses will report boosted apertures to the camera body but fast lenses will report pre-boost apertures. We won't show f/0.9 with a f/1.2 lens attached, but show f/1.2 instead.

Example:

a) EF 85/1.2L attached, camera display = f/1.2, physical aperture (lens + Speed Booster^® combined) = f/0.85.

b) Sigma 35/1.4 attached, camera display = f/1.0, physical aperture (lens + Speed Booster^® combined) = f/1.0.

• 4. Some improperly-made M42 screw mount adapters may short the electronic contacts of the Speed Booster^® and cause damage to the Speed Booster^® and/or camera body.
• 5. Many manual focus lenses (e.g. OM 28/2.8, OM 50/1.8, Leica R 15/3.5) have rear protrusions (spikes, levers, other appendages) which would damage the optics and/or housing of Speed Booster^®  They need to be modified before they can be safely used on Speed Booster^® Check and make sure there are no rear protrusions from the adapter/lens combination before using on Speed Booster^®. Scratches and damages caused by rear protrusions on Speed Booster^® are not covered by warranty.

WARNING

To update the firmware of a Canon EF lens downloaded from Canon's web site, use Canon's own adapter. While a Metabones Speed Booster has been tested for this use case scenario it is not guaranteed to work and not supported.

List of manual focus lenses which REQUIRE MODIFICATION to be used on Speed Booster^®

Many manual focus lenses have rear protrusions (spikes, levers, other appendages) which would damage the optics and/or housing of Speed Booster^® They need to be modified before they can be safely used on Speed Booster^® Check and make sure there are no rear protrusions from the adapter/lens combination before using on Speed Booster^®. Scratches and damages caused by rear protrusions or by poor quality adapters are not covered by warranty. The following is an incomplete list of lenses known to be incompatible.