Metabones Canon EF to Micro Four Thirds T Speed Booster XL 0.64x MB_SPEF-M43-BT3

Metabones EF - MFT T Speed Booster XL 0.64x (MB_SPEF-M43-BT3)

A Micro Four Thirds mount Speed Booster® adapter designed specifically for the Panasonic GH4 and selected Micro Four Thirds cameras, featuring a 0.64x magnification. It employs an advanced 6-element optical design to deliver exceptional optical performance at apertures up to f/0.80, setting a new standard for Micro Four Thirds format lenses.

Key Benefits

• Reduces the Panasonic GH4 full-frame crop factor from 2.0x to 1.28x, effectively converting the camera to APS-H format.
• In Cinema 4k video mode, reduces horizontal crop factor from 2.34x to 1.50x, transforming the GH4 into a super-35 format 4k cine camera.
• Increases lens speed by 1⅓ stops, achieving a maximum output aperture of f/0.80 with an f/1.2 lens (e.g., a 50mm f/1.2 becomes a 32mm f/0.80).

Features

• Increases maximum aperture by 1⅓ stops.
• Improves Modulation Transfer Function (MTF) for sharper images.
• Makes lenses 0.64x wider.
• Built-in electronics enable lens aperture control via camera body.
• Powered solely by the camera body; no external power required.
• Equipped with a high-performance 32-bit processor and efficient switched-mode power supply.
• Interior coated with flocking to minimize internal reflections.
• Detachable tripod foot compatible with Arca Swiss, Markins, and Photo Clam ball heads.
• Supports a wide range of Micro Four Thirds cameras including Panasonic GH4, GH3, G3, G5, G6, G10, GF3, GF5, GF6, GX1, Olympus E-PL7, Blackmagic Cinema Camera, and Blackmagic Pocket Cinema Camera.

Compatibility and Design

• Redesigned from the Blackmagic-specific 0.64x BMCC Speed Booster to increase working distance by 1mm, preventing interference with camera shutter mechanisms.
• Optimized optics for a 4mm Micro Four Thirds filter stack thickness (vs. 2.4mm in Blackmagic cameras).
• Expanded image circle diameter to 21.63mm, fully covering the 17.3mm x 13mm Four Thirds sensor format with high image quality, including the Panasonic GH4's Cinema 4k video mode.
• Note: Some Micro Four Thirds cameras remain unsupported due to mechanical clearance limitations.

Supported Lens Types

• Canon EF lenses including Image Stabilization (IS) lenses.
• Electronic manual focusing lenses (e.g., EF 85mm f/1.2L II, discontinued EF 50mm f/1.0L).
• EXIF data transmission (focal length, aperture, zoom range).
• Distance and zoom display on compatible camcorders.
• Contax N and Contax 645 NAM-1 lenses modified to Canon EF by Conurus.
• Sigma, Tamron, and Tokina lenses in Canon EF mount.
• External 5 Volt power supply support for passive Micro Four Thirds camcorders.

Unsupported Features and Lenses

• Autofocus functionality.
• EF-S lenses (some may require modification).
• Lens corrections such as peripheral shading, chromatic aberration, and distortion.
• Focus confirmation chips (e.g., Dandelion).
• M42 screw mount adapters (risk of electronic contact shorts).
• Stacking of non-Metabones/non-Conurus mount adapters.
• Tamron SP 17-50mm F/2.8 XR Di II VC lens.

Additional Notes

• Lenses must support distance information for distance and zoom display features.
• Third-party zoom lenses may require registration with the Speed Booster/Smart Adapter to detect maximum aperture.
• Designed to cover a 17.3mm x 13mm sensor.
• Manual focus lenses with rear protrusions must be modified to avoid damage to the adapter.
• External 5 Volt MicroUSB power supply can be used for passive MFT camcorders (not included; compatibility not guaranteed).
• For lenses faster than f/1.8, the camera will display pre-boost aperture values rather than boosted apertures.

Technical Specifications

Magnification

0.64x

Crop Factor (Full Micro Four Thirds format)

1.28x

Crop Factor with GH4 in Cinema 4k (4096 × 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 × 13.0 mm (full Micro Four Thirds format)

Physical Dimensions

6.7 cm × 2.4 cm (length × diameter)

Weight

170 g