Here’s a surprising new innovation, Speed Booster, just launched by the lens accessories producer Metabones. The Speed Booster allows you to mount a reflex lens onto a compact hybrid APS-C or Micro 4:3 with a reduction coefficient of 0.71x which allows you to find a good approximation of the 35mm focal equivalent, and there’s more. The Speed Booster allows you to gain one f stop aperture in the process!
Metabones Speed Booster is indeed a quite magical accessory if they hold true to their hype. It allows you to mount your full frame reflex lenses onto a hybrid APS-C or micro 4:3 while compensating more or less the difference of framing with a COI sensor as apposed to a full frame sensor. It also allows you to gain one full f stop of diaphragm opening, a bonus which is sure to seduce more than just a few photographers. The benefits don’t stop there as Metabones promises us that with their adapter they give better definition for a compact hybrid than adapters presently on the market, even same-brand ones! The first version of adapter to reach the market in the next few weeks is for mounting Canon EF lenses onto a Sony NEX. This first adapter will be commercialized by Metabones for $599 (450,€+/-). We’re sure that this predicts a sure success as they plan to produce adapters for Nikon F, Leica R, Contax …lenses to mount onto diverse 4:3 hybrids and the premium compacts from the Fuji X line, such as the Fujifilm X-Pro1 and X-E1.
In practice the Speed Booster commercialized by Metabones acts in the inverse sense of a telephoto-adapter which multiplies its focal length and reduces the wide open f stop. It acts as an optic converter, which will reduce the quantity of aberrations produced by a purely mechanical converter. Thanks to the reduction in size of image circle needed to cover. The concept is compatible with all 35mm lenses, also to those lenses designed for APS-C reflexes on condition that they don’t show vignetting because of being designed for an optic circle smaller than a reflex sensors capture size.
The Speed Booster mobilizes an optic formula composed of 4 elements in 4 groups and works even with extremely sensitive lenses up to f 1,2 like the famous Canon EF 85mm f 1,2L. It will also be more compact than a classic converter because its design is optic. Taking into account that it will reduce the focal length by a coefficient of 0,71x, and there’s a focal length increase of 1,5x for a APS-C sensor and 2x for micro-compact 4:3, its use will only increase focal length by 1,1 with an APS-C sensor and 1.5x for a 4:3. To give an example, a 24mm mounted on Sony NEX-6 would become a 26.4mm with this adapter as opposed to 36mm otherwise.
On the electronics side, Metabones has done things well with the first generation of adapters Speed Booster that will see the light of day. They’ll be able to pilot the diaphragm openings of the Canon EF lenses from the Sony NEX and be able to benefit from its optic stabilizer as well as the autofocus. The latter will react with a lot less speed than normal. Nikon F series lenses will prove to be a bit more difficult, with a compact hybrid requiring manual usage and deprivation of the lenses autofocus and image stabilization.