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Metabones T Speed Booster XL 0.64x - Canon EF to Micro Four Thirds (MFT) Adapter

Abel Code: MB-SPEF-M43-BT3
Mfr. Code: MB_SPEF-M43-BT3
Estimated to Ship – 4-6 weeks
Adapts Canon EF Mount to Micro 4/3 Mount with a magnification of 0.64x, increasing the speed of any attached lens by 1-1/3 stops.
Key Highlights
  • Canon EF to Micro Four Thirds (MFT)
  • 0.64x magnification
  • Reduces crop factor 1.28x
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The Metabones T Speed Booster XL 0.64x - Canon EF to Micro Four Thirds (MFT) Adapter is designed exclusively for the Panasonic GH4 and other selected Micro Four Thirds cameras (refer to the below camera compatbility table), with a magnification of 0.64x. The Speed Booster XL 0.64x uses an advanced 6 element optical design to achieve extraordinary optical performance at apertures up to an incredible f/0.8, a new record for Micro Four Thirds format. 

The new Speed Booster XL 0.64x reduces the full-frame crop factor of the Panasonic GH4 from 2.0x to 1.28x, thus effectively transforming these cameras into APS-H format.  When the GH4 is used in Cinema 4k video mode the horizontal full frame crop factor is reduced from 2.34x to 1.50x, thus effectively transforming the GH4 into a super-35 format 4k cine camera.  In addition, the speed of any attached lens is increased by 1-1/3 stops, with a maximum output aperture of f/0.80 when an f/1.2 lens is used.  For example, a 50mm f/1.2 becomes a 32mm f/0.80, which is the fastest aperture available for full size Micro Four Thirds format.

The Speed Booster XL 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 1-1/3 stop
    • Increase MTF
    • Makes lens 0.64x wider
    • Patented 6 element/4 group optical design by Caldwell Photographic in the USA
    • Supports 4k video mode with DX lenses (except on GH5)
  • 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 through 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
  • Limitations:
    • Supports only Panasonic GH5, GH4, GH3, G3, G5, G6, G7, G10, GF3, GF5, GF6, GX1, GX8, GX80/GX85, Olympus E-PL7, PEN-F, Blackmagic Cinema Camera with Micro Four Thirds mount, Pocket Cinema Camera and Micro Cinema Camera
    • EF-S lenses require modification to fit or may remain incompatible even after modification (but third party DX lenses can be used without modification)
    • On GH5, Speed Booster XL can be used with full frame lenses only; DX lenses are unable to cover full-sensor-width readout + in-body image stabilizer (IBIS)
    • EF-S and third party DX lenses does not cover the full Micro Four Thirds sensor in still photo and FHD video (but will cover 4k video mode on GH4, GX8 and GX80/85)
    • No video AF for Olympus
    • AF may not work if the maximum aperture of the lens plus any EF Extender or other teleconverter attached is smaller than f/8 before boost or smaller than f/5.1 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;a n external microphone is recommended for video
    • Use of Canon Cinema lenses such as CN-E 18-80mm T4.4 L 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



The Speed Booster XL 0.64x is similar to the Blackmagic-specific 0.64x BMCC Speed Booster (MB_SPEF-BMCC-BM1), but has been completely re-designed to meet the following requirements:

  • The working distance has increased by 1mm to permit use on the Panasonic GH4 and a number of other Micro Four Thirds cameras without touching the flexible outer cover of the camera’s shutter mechanism
  • The optics are optimized for a standard Micro Four Thirds filter stack thickness of 4mm rather than the 2.4mm found in Blackmagic cameras
  • The image circle diameter has been increased to 21.63mm so that the full 17.3mm x 13mm Four Thirds format is covered; this has been achieved while maintaining unusually high image quality over the 17.4mm image circle used by the Panasonic GH4 in its Cinema 4k video mode

Although the Speed Booster XL 0.64x has extra clearance compared to the 0.64x BMCC Speed Booster, there are still a number of Micro Four Thirds cameras that are not supported due to mechanical clearance issues:

  • JVC: 
    • GY-LS300
  • Olympus:
    • E-M5, E-M1, E-M10, E-M5 II, E-M1 II
    • E-P1, E-P2, E-P3, E-P5
    • E-PL1, E-PL2, E-PL3, E-PL5, E-PL6
    • E-PM1, E-PM2
  • Panasonic
    • AF100
    • GH1, GH2
    • G1, G2
    • GF1, GF2, GF7, GF8, GF800/850/9
    • GM1, GM5

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
  • Community Tested:
    • 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:

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


What's in the Box

  • Metabones T Speed Booster XL 0.64x - Canon EF to Micro Four Thirds (MFT) Adapter
  • Front Cap
  • Rear Cap
  • Hex Key (Tripod Foot)


Key Highlights

  • Canon EF to Micro Four Thirds (MFT)
  • 0.64x magnification
  • Reduces crop factor 1.28x
  • Increases max. aperture by 1.33 stop

Lens Characteristics

Max Aperture F-stop:
f/0.8 - when using f/1.2 lens
Elements & Groups:
6 elements in 4 groups
Magnification Ratio:

Mount / Optical Lens Adapters

Adapter Mount Side B (Camera):
MFT - 1.28x crop factor
Adapter Mount Side A (Lens):
Adapter Type:
Optical Adapter
Mount Adapter
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