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)

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 do 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. An external microphone is recommended for video.
• Use of Canon Cinema Compact-Servo 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

Autofocus Lens Compatibility List

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