Metabones Nikon G to Micro Four Thirds Speed Booster ULTRA 0.71x

The Metabones Nikon G to Micro Four Thirds Speed Booster ULTRA 0.71x is a focal reducer adapter that mounts Nikon G-mount lenses onto Micro Four Thirds cameras, compressing the image circle to increase effective aperture by one stop and reduce the field-of-view crop compared to a standard dumb adapter. It weighs 170g.

What does the 0.71x Speed Booster actually do?

A Speed Booster is a focal reducer — it takes the light cone from a full-frame or APS-C Nikon G lens and concentrates it onto the smaller MFT sensor. The 0.71x factor means a 50mm f/1.8 Nikon lens effectively behaves like a ~35mm f/1.3 on your MFT body relative to a plain adapter. You get a wider field of view than a standard adapter and one extra stop of light, which is a real advantage in low-light shooting. Note that the MFT 2× crop factor still applies — the Speed Booster reduces its impact rather than eliminating it entirely.

Who is this for?

If you shoot on a Micro Four Thirds body — think Panasonic GH or G series, or Olympus/OM System cameras — and you already own a set of Nikon G lenses, this used adapter lets you put that glass to work without selling it. It's also popular with video shooters who want a faster, wider look from their existing Nikon glass on a compact MFT rig.