No waiting around for a conclusion here. I'd like to make one thing clear from the start. The Metabones Nikon G to Micro Four Thirds Speed Booster XL 0.64x is a fantastic piece of kit and is a shoe in for the Soundimageplus accessory of the year. I don't recommend much, but if you use m4/3 and third party, manually focused, Nikon or Canon lenses for stills and / or video, then you have to have one of these. What it does is nothing short of extraordinary. It gives you a stop more light gathering, widens 'full-frame' lenses so that you get a 1.3x crop instead of the normal 2x, gives corner to corner sharpness and pretty much means you have a different camera that produces images with that 'full-frame' look. It's not cheap but Brian Caldwell and Metabones have come up with an incredible piece of glass here. It's often stated that gear won't make you a better photographer, but with this little beauty, even that is possible! Now I wonder what would happen if they decided to make lenses with this technology included!!
Here's what it does
Above is a shot taken with my G7 and Nikon 20mm f/1.8G lens attached. Shot with an 'ordinary' adapter giving that usual 2x crop. The adapter has aperture control and it's shot wide open at f/1.8. This is approximately how a 40mm lens might perform on a 'full-frame' camera.
Above is a shot from the same place using the same lens and camera settings taken with the Metabones Nikon G to Micro Four Thirds Speed Booster XL 0.64x Now I get a much wider view with the 1.3x crop. This is now approximately how a 26.5mm lens might perform on a 'full-frame camera. Also check out the exif data. Same shutter speed, same aperture (wide open at f/1.8) but ISO 250 instead of ISO 640. Now that's actually slightly more than a 1 stop bonus. Pretty impressive, considering that the Speed Booster file is pin sharp as well.
The great advantage of this Metabones Nikon G to Micro Four Thirds Speed Booster XL 0.64x is essentially you get a new camera. You get a stop more light gathering, so that means that all ISO settings, including the higher ISO ones are very competitive with larger sensors and of course because the full-frame lenses are closer to their 'full-frame' coverage with the 1.3x crop, the images produced have a 'full-frame look.' There were some cameras with this crop, the Leica M8 and Canon 1D series being examples of this.
One thing should be borne in mind. Because of the extended camera end of the adapter it can't be used on all m4/3 cameras because it will get in the way of and damage the shutter. Unfortunately if you are an Olympus user you are out of luck, since it only works with one camera, the E-PL7. Panasonic has a lot more options. This adapter works fine with the G3, G5, G6, G7 and G10, the GX1 (but not the GX7) the GF3, GF5 and GF6 (but not the GF7) and the GH3 and GH4. This is all to do with the slightly different ways the cameras are designed. Panasonic and Olympus obviously have no regard to compatibility with the Metabones, since they make no money from people who use it. Probably the reverse in fact.
So, if you are happy with manual focus, this is a great accessory and one that really stretches your m4/3 camera (assuming it's compatible) Creative photographers and videographers will realise the potential of this for their work and I'll certainly be exploring what it can do. It does of course lead to speculations as to whether they can ever achieve a 0.5x speed booster, which would of course mean no crop factor at all with 'full-frame' lenses. Now just imagine that!!
N.B. I should make it clear that I have no relationship with Metabones and like all the gear I review I bought it myself. I don't get freebies or sent stuff to review by Metabones or anybody else for that matter. (If only!!!)
N.B + If you wondering what the Leica flash gun is doing on the camera, it has an LED light in it which gives an additional extra stop of light for close up subjects.