Just a few months ago, a company many are familiar with for their smart Canon EF to Sony NEX adapters, Metabones, introduced a brand new adapter with an optical component that can make full-frame lenses faster, wider, and sharper by focusing them onto a smaller format like APS-C/Super 35mm. Metabones also announced they were going to be releasing a Micro 4/3 to Nikon, Leica R, Contax C/Y, Contarex, ALPA, and Rollei Speedbooster adapter. Originally set to be released in the first half of 2013, it looks like we're going to have to wait a bit longer.
You can watch a review of the Metabones EF adapter below from Bryant Naro:
Video is no longer available: vimeo.com/57349698
Here is Metabones on the MFT Speedbooster:
We apologize but the m4/3 schedule is slipping. Manual focus lenses such as Nikon, Leica R, Contax C/Y, Contarex, ALPA and Rollei will be supported in the second half of 2013.
Canon EF lens (but not EF-S) support is planned in the future, but we do not have an estimated date yet.
The m4/3 version also reduces focal length by a 0.71x factor. So, the combined focal length multiplier of a m4/3 camera and Speed Booster is 1.4x. (2x from camera x 0.71x from Speed Booster.) The optics are optimized for the smaller sensor size.
If you're wondering how the adapter actually makes lenses wider and faster, they've gone on to explain just that:
Does the Speed Booster™ increase only T-stop of the lens leaving F-stop unchanged?
This is one of the common misconceptions about the Speed Booster™. However there is a contradiction right within that assertion since T-stop cannot be any faster than F-stop. It is not possible to experimentally observe a T-stop increase unless the lens has a corresponding F-stop increase.
The logic of the allegation is that since the depth-of-field of the lens does not change, therefore neither does the F-stop of the lens (untrue). What had never been under any dispute was that the T-stop of the lens did increase, as could be seen with the increased exposure in the resulting footage or photograph.
Before we clear up this misconception, let's find out why there is so much confusion in the first place. Focal length, maximum aperture and depth-of-field are physical quantities that are independent of sensor size. These quantities do not care whether a full frame, APS-C or m4/3 sensor sits behind the lens.
Speed Booster™ makes the focal length 0.7x shorter. F-number is simply focal length divided by entrance pupil diameter. Since the former reduces by a factor of 0.7x but the latter remains the same, F-number also becomes 0.7x smaller, or one stop faster. The F-stop increase is real.
Note that a 35/1.0 lens (from 50/1.4 + Speed Booster™) will always have shallower depth-of-field than a straight 35/1.4 lens at any given distance.
Eventually I'm sure we will see a Speed Booster for Canon, but if you've got one of the other lenses that will be supported, you'll have to wait until the second half of 2013. The Micro 4/3 adapter will work well for cameras like the GH2, GH3, AF100, Blackmagic Cinema Camera MFT, and the newly announced Blackmagic Pocket Camera, which has an MFT mount and a sensor about the size of Super 16mm. The Micro 4/3 Speed Booster also has the advantage of being able to take lenses that were designed specifically for APS-C sensors, since MFT is smaller than APS-C.
You can find more info about the Speed Booster line and buy one for NEX or Fuji cameras using the links below.
[via 4/3 Rumors]