Metabones Speed Booster Adapter Makes Your Lenses Faster, Wider and Sharper

If you read the title and thought “huh?” you’re not the only one. Hearing that an adapter can actually make your lenses faster and wider sounds a bit like photography science fiction, but it’s true and it’s getting some serious attention online — it’s Metabones’ new Speed Booster.
If you want to get into the nitty gritty details of how it works you can find the whole white paperhere. The TL;DR version, however, goes something like this:
The Speed Booster is what’s called a focal reducer (see diagram below), basically an inverted teleconverter. Where a teleconverter increases magnification, the Speed Booster has a magnification of x0.71. Because of this, more of the image and more light is able to fall onto the sensor

When you attach a full-frame lens to the adapter, it will give your mirrorless’ APS-C or MFT sensor nearly full-frame coverage out of that lens, while increasing the amount of light hitting the sensor by one stop. So a 50mm f/1.4 effectively becomes a 35mm f/1.0.

Because of the way the adapter works you’ll have to use full-frame lenses if you’re using a Sony NEX body. However, micro four thirds speed boosters are also in the works, and those sensors are small enough that you can attach EF-S or DX lenses to the other side.
The Speed Booster will cost you $600, and should be available starting sometime this month. The EF to E-Mount Speed Booster is already up for pre-order; however, speed boosters should releasing shortly for both Canon EF and Nikon FX lenses adapting to both E-Mount and Micro Four Thirds systems.

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Thanks for sending in the tip, Troy!