A new Micro-4/3 mount Speed Booster^® adapter designed exclusively for the Panasonic GH4 and other selected Micro Four Thirds cameras (refer to the below camera compatibility 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/0.80, 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 1¹/₃ 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.

Compatibility

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.  This is summarized in the table below, which is color-coded so that Green means the camera is supported and Red means the camera is not supported. 

Note that many of the Red-coded cameras actually do function, but there is a minor interference with the protective shutter cover.  Although slight contact with the shutter cover appears to have no effect on the functioning or cosmetics of either the camera or the Speed Booster we cannot support these combinations due to possible risk of damage.

Select the correct EF-MFT Speed Booster fits for your camera:

Autofocus with an Optimum Balance of Accuracy, Speed, Consistency and Reliability

New in Speed Booster XL for Canon EF Mount to Micro Four Thirds is autofocus support, subject to certain limitations (see table above for details). We are pleased to report that 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 our first and foremost priority is accuracy, we are able to make great strides in autofocus speed as well.

Autofocus Lens Compatibility List

The following table lists lenses which has been tested. Other lenses not listed here typically works well, too.

* with smooth iris support

** CN-E Compact-Servo lens with some of MFT cameras may require external power to autofocus

Manual Focus Lens Compatibility

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

Metabones Speed Booster XL 0.64x Specifications:

Magnification:  0.64x

Crop Factor for Full Micro Four Thirds format:  1.28x

Crop Factor with GH4 in Cinema 4k (4096 x 2160) Video Mode:  1.5x

Maximum Output Aperture:  f/0.80 (with f/1.2 lens attached)

Rectilinear Distortion:  < 0.8%

Lens Elements/Groups:  6/4

Length Reduction:  6.2 mm

Camera Mount:  Micro Four Thirds

Image Format:  17.3 mm x 13.0 mm (full Micro Four Thirds format)