The Metabones Speed Booster promises to make your SLR lens faster, increasing its maximum aperture by a whole stop.
We'll be the first ones to admit that lens adapters, teleconverters and any other related accessories don't necessarily make headline-grabbing news. The Metabones Speed Booster appears to be something far removed from your traditional adapter though.
Firstly, the Speed Booster allows you to connect an SLR lens to a mirrorless interchangeable lens camera (ILC). So far, this is pretty normal. But the adapter goes one step further by actually increasing the maximum aperture of your lens by one whole stop. So for example, an f/4 lens instantly becomes an f/2.8 lens, while an f/1.8 becomes f/1.2. What this means in practical terms is that users will be able to get better performance in low light.
The key to this optical wizardry lies in the configuration of the Speed Booster. It has a focal length multiplier of 0.71x, which means that the resulting image, once it passes through the adapter, is actually smaller. However, given the crop factor of a sensor such as APS-C, combining these multipliers gives 1.09x, which is almost that of full-frame.
Too many confusing numbers? Don't worry; all you need to know is that the Speed Booster gives a wider field-of-view and a one stop increase in maximum aperture. At the moment there is a Canon EF/Leica R/Alpa to Sony NEX adapter and Leica R/Alpa to Fuji X adapter available, with Nikon and Micro Four Thirds adapters arriving in the coming months.
Initial tests appear to be giving good results, with enthusiast website EOSHD grabbing this video with the adapter on the Sony FS100, and comparing it with footage shot on the full-frame Canon 5D Mark III. Another key advantage is that the adapter provides the full-frame look from photos and video without the expense of buying a full-frame camera.
The Canon EF to E mount adapter is available for US$599 from the Metabones website.