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 paper here. 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.

Thanks for sending in the tip, Troy!

  • Anthony Lam

    i want a EF to EF mount

  • Jesse

    So what this is doing is taking the lens, moving it closer to the sensor than it would be designed to be, adding a glass element that refocuses the light to a smaller area.
    For an SLR however, adding an adapter would mean the lens would be moving further from the sensor, spreading the light and making it “slower, softer, longer”.

  • Martin M

    You’ve got it all wrong, the adapter doesn’t physically move the lens closer to the sensor because it is mounted between the lens and the sensor. The adapter refracts inwards and constricts the light circle and then conducts the (amplified intensity) light to the sensor. (That’s why the adapter has two glass elements). The light rays have to be always perpendicular to the sensor, so I don’t see the point why it couldn’t be done for DSLRs. So, in theory this doesn’t anything whatsoever to do with the flange distance, except maybe with the focusing…

  • Martin M

    Yes, that’s true, plus check this out, there’s a website called DXOMark that deals with sensors and low light performance, Think about this this way: Take APS-C camera and a full frame (D7000 and D600). Take the same lens (50mm f/1.8). If you mount this lens on D7000 with this adapter, it will no longer be f/1.8, but f/1.2. If you mount it on D600 it remains f/1.8. D7000 has a high ISO score about 1150. D600’s score is about 2800. Cause this adapter would make the SAME LENS faster by 2 times, the efficiency of the two systems APS-C and full frame would be about the same. The D7000 + 50mm f/1.2 would yield a high ISO result of 2*1150=2300, which is almost indistinguishable then the D600 + 50mm f/1.8. ;)

  • Jesse

    It actually does change the distance from the sensor. If you compare its size to metabones regular EF to E it is shorter.

  • hugh crawford

    Kodak has a patent on this that they have used to kill previous attempts to market things like this, although it’s pretty easy to make one by taking a 1.4x teleconverter apart and using the guts installed backwards in an full frame to NEX adapter. The trick is finding one that is physically short enough to fit.

    “Another glass between lens and sensor, another chromatic aberrations, distortions, and so”

    No actually it can decrease the aberrations and distortions and actually increase sharpness just by virtue of putting the same image information into a smaller area , this design is used in some high end lenses.

  • EricD

    It’s just a Teleconverter with ‘negative’ (<1) magnification. Handy !

  • Craig Incardone

    Ok! Love this idea! I own a Sony FS100 and would love to have my Nikon lenses
    at full frame for my cam! Is the Adapter only usable with manual iris lenses? Which
    is pretty much all I have. Can’t wait to get one!!!!!!

  • Craig Incardone

    Everyone needs to remember that when the 35mm adapter systems were out there
    they were up to $6K just to get that film look! You’re cam now weighted near
    30lbs and looked like a joke. So this lens adapter you guys are doing is at
    reasonable price for what it can do! Good work!

  • Jesse

    For a quick reference, think of it as the complete opposite of a teleconverter. Where a teleconverter pulls the lens further away from the sensor, decreases light output and image quality (and refocuses the magnified light for the distance. this pushes it closer (and refocuses the light) increases quality and light output.

  • COREHAZA Productions

    I don’t understand how you all think this is expensive…to buy a single lens that could achieve anything even similar your looking at over $1500. This adapter allows you to put it on all your lenses effectively making L-series and high end glass, well not as important anymore.

  • Jim A.

    If I can get this to mount my Canon glass on my EM-5, I’ll pay $600 with a smile. Especially if I get aperture control and autofocus. My 300/2.8 becomes a 426mm/1.8? Yeah, sign me up for that…Soon please!

  • Gov

    Not really. A teleconverter just moves the lens further away from the film/sensor, but has no optics.

  • uksnapper

    Dont forget the inverse square law.
    If you put an adapter between lens and sensor you effectively make the aperture smaller

  • since1969

    Nikon’s revered 50mm f/1.4 costs $380 and this costs $600. Are you going to be able to find a 35mm f/1.0 for $980? (Never mind that for that grand total you’d have both fixed-focal-length lenses.)

    Hint: Nikon’s 35mm f/1.4 retails for about $1450.

  • since1969

    You’re forgetting that for your full-frame camera, you’re still going to need lenses. And you’d be a fool to buy a full-frame camera and throw a bunch of slow glass on it. So $2000 later this product will actually be MORE desirable to you than it is now.