icon account icon cash icon cart icon cart icon search main arrow arrow check icon camera icon light icon audio icon computer icon storage icon discount icon facebook icon twitter icon linkedin icon vimeo icon youtube icon instagram icon google plus icon share icon email icon print icon time icon phone icon email-m icon marker-m icon pdf icon remove icon comment icon out icon-status icon-star icon-switch pie-chart line-chart icon-user icon-user-1 icon-warning icon-heart expand-arrow-1 expand-arrow-2 icon-upload icon-download icon-none icon-date-scheduled icon-date-available icon-is-hazardous

Metabones T Speed Booster ULTRA 0.71x - Canon Full Frame EF to MFT Mount Adapter

Abel Code: MB-SPEF-M43-BT4
Mfr. Code: MB_SPEF-M43-BT4
In Stock
Available In Store | NY
Adapts Full Frame Canon EF Mount lens to Micro Four Thirds (MFT) Mount with a magnification of 0.71x, and reduces the crop factor of mirrorless MFT cameras from 2x to 1.4x.
Key Highlights
  • Canon Full Frame EF to MFT
  • 0.71x magnification
  • Reduces crop factor 2x to 1.4x
Add To Wishlist


The Metabones T Speed Booster ULTRA 0.71x - Canon Full Frame EF to MFT Mount Adapter features a new optical design with advanced 5 element/4 group configuration incorporating ultra-high index, tantalum-based optical glass to achieve exceptional performance with improved corner sharpness and distortion, and reduced vignetting. It is specifically optimized for the Micro Four Thirds sensor and filter stack.

The Speed Booster ULTRA has a magnification of 0.71x, effectively reducing the crop factor of mirrorless MFT Mount cameras from 2.0x to 1.4x.  However, the new ULTRA design makes very effective use of exotic materials at the furthest limit of glassmaking technology, and is well corrected for use with virtually all full frame SLR lenses, regardless of aperture. It is also compatible with many DX and APS-C format lenses (provided the image circle of the lens is large enough).

The optical performance of this Speed Booster improves the MTF of any lens attached to it, including the latest generation of ultra performance SLR lenses such as the Zeiss Otus series. It also features autofocus support, subject to certain limitations. Panasonic Micro Four Thirds camera bodies are capable of autofocusing accurately even if the maximum aperture of the Speed Booster and the lens combined is in the sub-f/1.0 range. Although the first and foremost priority is accuracy, Metabones has been able to make great strides in autofocus speed as well.


  • Optical/Mechanical:
    • Increase maximum aperture by 1 stop
    • Increase MTF of any lens attached
    • Makes lens 0.71x wider
    • Patented 5 element/4 group optical design incorporating ultra-high index tantalum-based optical glass by Caldwell Photographic in the USA
    • Supports 16:9 video with DX lenses
  • Electronic:
    • Autofocus
    • Can be powered either by camera body or by third-party external 5V power source (not included)
    • Iris/aperture controlled by the camera body
    • Smooth iris support with the latest Canon (2009+), Tamron (SP series 2013+) and Sigma (2016+) lenses
    • Image stabilization (IS) lens support
    • Support for cameras with in-body image stabilization (IBIS), including Panasonic GX7, GX8, GX80/85 and Olympus cameras
    • Electronic manual focusing (e.g. EF 85/1.2L II and discontinued EF 50/1.0L)
    • EXIF (focal length, aperture, zoom range)
    • Distance and zoom display on camcorders (requires lenses supporting distance information)
    • Cinema EOS lens support (CN-E 18-80mm T4.4 L), including AF (requires external 5V power via micro USB port), auto iris and servo zoom
  • Other:
    • Detachable tripod foot compatible with Arca Swiss, Markins and Photo Clam ball heads
    • The opening is flocked with felt material to reduce internal reflection
    • Compatible with all MFT mount cameras, including GH4, OM-D, Blackmagic Cinema Camera, Blackmagic Pocket Cinema Camera and JVC GY-LS300
  • Limitations:
    • EF-S lenses require modification to fit or may remain incompatible even after modification (but third party DX lenses can be used without modification)
    • Some EF-S and DX lenses may not have sufficient image circle coverage for stills after widening by 0.71x (video will have enough coverage)
    • No video AF for Olympus
    • AF may not function if the max. aperture of the lens, plus any EF Extender or other teleconverter attached, is smaller than f/8 before boost or smaller than f/5.6 after boost
    • AFC (continuous AF) and AFF (flexible AF) modes are not supported, except on Olympus OM-D E-M1
    • Panasonic video AF may hunt more than a native lens or have unsatisfactory performance
    • Some Tamron lenses may have unsatisfactory AF accuracy
    • No support for Focus Stacking and Focus Bracketing on Olympus
    • On Olympus, other than E-M1, you may move the single AF point among any of the 81, but you may not multi-point AF; there is no restriction on E-M1 and Panasonic
    • Very early Olympus models (e.g. E-PL1) have no autofocus support
    • EF-mount lenses are not silent but may make audible click noises during autofocus operation and iris changes which may be picked up by the built-in microphone of the camera; an external microphone is recommended for video.
    • Use of Canon Cinema lenses such as CN-E 18-80mm T4.4L IS KAS S for still photography is not supported
    • Iris changes are in 1/8 stop steps which may be noticeable in video recordings. Programmed exposure mode and shutter priority exposure mode should not be used for video; this limitation does not apply to Cinema EOS lenses which permit fine resolution iris control, such as CN-E 18-80mm T4.4 L IS KAS S
    • No support for in-camera correction such as peripheral shading, CA and distortion
    • Designed to cover a 24mm image circle, JVC GY-LS300 needs to have VSM configured to 86% (4k) when using a true Super 35 lens such as Canon CN-E 18-80mm T4.4L IS KAS S; higher VSM settings is possible with full-frame lenses, but will be operating outside of the design parameters of the ULTRA optical formula
      • Many APS-C/DX lenses do not have adequate coverage at 86% (4k) and on JVC with ULTRA the use of full-frame or true Super 35 lenses is advised

Tested Camera Bodies:

  • Blackmagic: Micro Cinema Camera, Pocket Cinema Camera
  • JVC: GY-LS300
  • Olympus: E-M1, E-M1 Mark II, E-M5, E-M5 Mark II, E-M10, PEN-F, E-P5, E-PL3
  • Panasonic: GX1, GX7, GX8, GX80/85, GH1, GH4, GH5, G2, G3, G5, G7, GM1, GF3, AF100

NOTE: Unlisted cameras have not been fully tested for compatibility.

Autofocus Lens Compatibility:

  • Accurate:
    • Canon EF 8-15mm f/4L USM Fisheye*
    • Canon CN-E 18-80mm T4.4L IS KAS S* (requires external power to autofocus)
    • Canon EF 20-35mm f/3.5-4.5 USM
    • Canon EF 24-105mm f/4L IS USM
    • Canon EF 28-80mm f/3.5-5.6 II
    • Canon EF 35-80mm f/4-5.6
    • Canon EF 40mm f/2.8 STM*
    • Canon EF 50mm f/1.2L USM
    • Canon EF 50mm f/1.4 USM
    • Canon EF 50mm f/1.8 STM*
    • Canon EF 70-200mm f/2.8L IS II USM*
    • Canon EF 70-300mm f/4-5.6L IS USM*
    • Canon EF 85mm f/1.2L II USM
    • Canon EF 100mm f/2.8L IS Macro USM*
    • Canon EF 100-400mm f/4.5-5.6L IS USM
    • Canon EF 100-400mm f/4.5-5.6L IS II USM*
    • Canon EF Extender 1.4x III
    • Canon EF Extender 2x
    • Sigma 18-125mm f/3.8-5.6 DC HSM
    • Sigma 24-105mm f/4 Art
    • Tokina AT-X PRO 11-16mm f/2.8 DX II
  • Tested by the Community:
    • Canon EF 70-200mm f/2.8L IS USM (Mark I)
    • Canon EF 85mm f/1.2L USM (Mark I)
    • Canon EF 200mm f/2.0L IS USM
    • Canon EF 300mm f/2.8L IS USM (Mark I)
    • Canon EF 400/2.8L IS USM (Mark I)
  • Accurate only on newer cameras (such as Panasonic G7, GX8 and GX80/85):
    • Canon EF 70-200mm f/4L USM (non-IS)
    • Canon EF 135mm f/2L USM
    • Canon EF 200mm f/2.8L II USM
    • Canon EF 300mm f/4L IS USM
    • Canon EF 400mm f/5.6L USM
    • Sigma 18-35mm f/1.8 DC Art
    • Sigma 50-100mm f/1.8 DC HSM Art 016*
    • Tamron SP 15-30mm f/2.8 VC USD A012*
    • Tamron 18-270mm f/3.5-6.3 VC PZD B008
    • Tamron SP 45mm f/1.8 VC USD F013*
  • Manual Focus Only:
    • Contax N lenses modified by Conurus
    • Tamron SP 17-50mm f/2.8 VC B005
    • Zeiss ZE lenses
  • Require external USB power supply owing to high current consumption (AF inaccurate):
    • Tamron 28-300mm f/3.5-6.3 XR Di VC A20
      • VC function of Tamron 28-300/3.5-6.3 XR Di VC model A20 may not operate, due to usually high current requirement
    • Tamron 150-600/5-6.3 VC USD A011*
  • Inaccurate:
    • Canon EF 28-70mm f/3.5-4.5 II
    • Canon EF 50mm f/1.8 II
    • Canon EF 100mm f/2.8 Macro USM
    • Sigma 50mm f/1.4 EX HSM
    • Tamron 18-250mm f/3.5-6.3 Di II Macro A18
    • Tamron 18-270mm f/3.5-5.6 Di II VC B003
    • Tamron SP 24-70mm f/2.8 Di VC USD A007
    • Tamron 28-300mm f/3.5-6.3 XR Di Macro A06
    • Tamron SP 70-200mm f/2.8 Di VC USD A009*
    • Tokina AT-X PRO 11-16mm f/2.8 DX (I)
  • Not Supported:
    • Focus confirmation "chip" (e.g., Dandelion)
  • Does not fit, even after modification:
    • Canon EF-S 18-135mm f/3.5-5.6 IS Nano USM

*NOTE: Lenses marked with an asterisk support smooth iris.

IMPORTANT NOTE: 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.

Manual focus lenses which REQUIRE MODIFICATION to be used on Speed Booster:

  • Leica R 
    • Super-Elmar-R 15mm
    • Elmarit R 28/2.8
    • Elmarit R 35/2.8
    • Summicron R 50/2
  • Nikon F
    • 20/2.8 AI-S
  • Olympus OM
    • OM 18/3.5
    • OM 21/2
    • OM 21/3.5
    • OM 28/2.8
    • OM 50/1.8
  • NOTE: Every Pentax K-mount lens has a protruding fin and an aperture lever, and does not fit.

What's in the Box

  • Metabones T Speed Booster ULTRA 0.71x - Canon Full Frame EF to MFT Mount Adapter
  • Front Cap
  • Rear Cap
  • Hex Key (Tripod Foot)


Key Highlights

  • Canon Full Frame EF to MFT
  • 0.71x magnification
  • Reduces crop factor 2x to 1.4x
  • Increases maximum aperture by 1 stop

Lens Characteristics

Elements & Groups:
5 elements in 4 groups
Magnification Ratio:

Mount / Optical Lens Adapters

Adapter Mount Side B (Camera):
Adapter Mount Side A (Lens):
EF - Full Frame
Adapter Type:
Optical Adapter
Mount Adapter
Finance Services

Finance Services

Customized financing from pros who understand this industry and your unique needs.



Get access to our tech services, support and training, on your terms, when you need it most.

AbelCine - Contact Sales

Have a question about Sales?

Contact us