Metabones original Speedbooster announcement was revolutionary, breathing new life into smaller sensors by increasing their field of view, light sensitivity and sharpness.
0.71x was the magic number, this level of magnification increases super35mm cameras like the FS100 and FS700 into full frame, opening a whole world of new opportunities including sub f/1.2 apertures and for the first time, Full Frame 4K video.
Towards the end of 2013 Metabones advanced further with Speedboosters specific to the Blackmagic Cinema Cameras. These provided much wider fields of view on both Pocket and Cinema version of the Blackmagic cameras. It was the first time Metabones included a new magnification increase in their speedboosters; 0.58x and 0.64x respectively.
Move to present day and Metabones has announced a new Speedbooster specifically for the Panasonic GH4. It to benefits from a 0.64x magnification, providing the flagship mirrorless camera with a very attractive x1.5 crop factor at 4K.
This brings the GH4 right inline with super35mm; the original x2 crop factor* was a stumbling block for many, as negotiating a completely new lens line or crop factor for current collection was both frustrating and expensive.
*Crop factor of x2 applying to 1080 mode on the GH4, not 4K.
As many well know, the Panasonic GH4 has two crop modes, one for 1080 and one for 4K, which are x2 and x2.34 respectively. Whilst the new Speedbooster provides 4K mode with a super35mm crop factor, it goes one further in 1080 mode offering a near APS-H crop factor of x1.28 (Canon 1D territory).
As expected from a new Metabones adaptor, the GH4 EF Speedbooster XL needs no additional power, carries focus, zoom and aperture information, as well as powering Image Stabilization for compatible lenses; like many (if not all) new Metabones adaptors it uses high quality patent pending Caldwell Photographic Optics.
Speaking of optics:
“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 1.33x stop increase is highly impressive; it will convert an f/1.2 prime into an astounding f/0.80.
To calculate the new field of view of your lenses, simply multiply the focal length by the new crop factors in each respective GH4 mode (1.28 in 1080, 1.5 in 4K). For example, a 50mm lens will become 64mm in 1080 mode, and 75mm in 4K mode.
Here is the specification list of the GH4 Speedbooster XL
- 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
- Lens Mount: Canon EF (EF-S not compatible)
- Image Format: 17.3 mm x 13.0 mm (full Micro Four Thirds format)
Despite the Speedbooster XL being marketed as an adaptor for the GH4, it will fit a host of other mirrorless cameras, the table below highlights fully compatible cameras in green:
Metabones state that others (including some of the above listed in red) may work, the physical connection between adaptor and camera will always mate if your camera has a Micro Four Thirds lens mount. However only the above listed in green will be compatible without any mechanical clashing of the adaptor and shutter/shutter cover.
By opening up the sensor to super35mm size and increasing the light sensitivity by 1 and 1/3 stop, the Metabones Speedbooster XL really makes the GH4 a whole different camera.
Users migrating from other cameras with a large EF lens collection have a much simpler transition, and super35mm users now have another credible option as a B or C camera that isn’t worlds apart in terms of crop factor or light sensitivity.