Metabones Speed Booster - New Focal Reducer Makes Lenses Faster, Wider, and Sharper
 

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Maybe free lunch exists after all. The Metabones Speed Booster is a new adapter for Micro 4/3 and Sony NEX that is designed to reduce the focal length of an adapted SLR lens while increasing the speed of the lens. This type of adapter, called a focal reducer or telecompressor, is essentially the opposite of a teleconverter.

The idea is not new. For example, the very early Nikon E series DSLR, co-developed with Fuji, used a 4X focal reducer to get the full angle of view and light collecting power of full frame lenses condensed to a 2/3" sensor, and Kodak has a 1994 patent describing a device similar to the Metabones Speed Booster.

To date, no one has been able to design a general use focal reducer that will work with fast lenses while effectively addressing optical aberrations, especially spherical aberration and field curvature. According to the white paper, the engineers behind the Metabones Speed Booster were able to create a focal reducer that accomplishes these goals by designing specifically for mirrorless cameras.

The Metabones Speed Booster reduces the focal length of an adapted lens to 0.71X, where X is the original focal lengh of the lens. At the same time, it increases the lens speed (virtual aperture relative to focal length) by one full stop. Thus a 35mm f/1.4 SLR lens fitted to the Speed Booster physically becomes a 25mm* f/1.0 lens.

*50mm equivalent angle of view on MFT, 38mm equivalent AOV on NEX

For more information, read the white paper: http://www.metabones.com/images/meta...te%20Paper.pdf

Not sure about the "free lunch"
 

The price mentioned was about US $599 - so not exactly cheap, but maybe price will drive down if someone does a non-AF version for manual focus lenses.
Cant wait to see some reviews, it certainly is another booster for mirrorless!

If it works, this could solve one of the big issues with m43--the lack of wide-angle legacy lenses. I know I'm interested, but probably not at $600!

Ray, if I've understood this correctly, the lenses you fit with the adapter must be DSLR lenses and not native µ4/3 (or NEX) lenses...

Yeah, just realized that and deleted my post. Oh well, no use to me.

-Ray

In addition to opening up some of the wide angle options, this is actually a pretty cool for the telephoto zoom side of the equation as well as it makes some inexpensive old legacy lenses fast telephotos ...

I don't exactly understand...

a) how it works
b) why it costs 600$

So what happens to a Noctilux?! Lol

As you point out this is nothing new - Olympus filed for a patent on a 0.5x focal reducer adapter in 2010. The question is will it work well.

I like to think that a 0.7x adapter doesnt really change a 35 1.4 lens into a 25 1.0 lens but instead makes it a 35 1.4 (35mm equivalent) on a camera with an APS C sensor.

This would be great news for Canon and Nikon because it would make their legacy lenses very attractive on their mirrorless product.

Question--will the DOF change in relation to the new f-stop or is it still equivalent to the old one?