Metabones has already provided shooters with a variety of Speed Boosters -- lens adapters that optically counteract crop factor, increase light transmission, and in many cases even maintain smart lens control. Now, Metabones has announced a new addition to the Speed Booster line: a Canon EF to Micro 4/3 mount model that will effectively allow the Panasonic GH4 (and other Micro 4/3 cameras) to have the field of view of a Super 35mm camera and also increase your lens' maximum exposure one stop. Metabones is also going to offer an equivalent adapter without the expensive optics just to control Canon lenses on your MFT cameras.
Previous Speed Boosters have effectively turned the 2.5K Blackmagic into a Super 35mm FOV camera, and brought similar benefits to the Blackmagic Pocket. Reid mentions that the Panasonic GH4 has a 2x crop in 1080p, but is actually an even tighter 2.3x crop when shooting 4K. After the new EF-to-MFT Speed Booster's 0.71x widening factor, the crop shooting 4K on the GH4 becomes 1.7-1.8x -- much closer to the crop on a standard APS-C or Super 35mm sensor, and when you're shooting 1080p, it's a 1.5x crop as compared to full-frame.
Here are some short pieces test driving the GH4 with variations of Speed Boosters -- the first by Andrew Reid:
Since the Nikon Speed Booster to MFT is essentially the same optics as the Canon model, there is plenty of footage out there already like this that can give you an idea of what you can expect (this is from Kristoffer Davidsson):
Video is no longer available: vimeo.com/101855745
At $600 for the new EF-to-MFT, this may be a desirable accessory for many owners of the GH4 looking to expand the scope, sensitivity, and lens options available to their cameras (though be sure to check their list of compatible lenses, as not all lenses can work with this adapter). If you're one such shooter or just plain curious, be sure to check out the links below for more details. Both the Speed Booster and Smart Adapter are also compatible with the previous incarnations in the GH line, as well as the BMCC, BMPCC, and Digital Bolex D16.
- Canon EF Lens to Micro Four Thirds Speed Booster -- Metabones
- Canon EF Lens to Micro Four Thirds Smart Adapter -- Metabones