Tuesday, August 20, 2013

Metabones Speed Booster Nikon G lens to Fuji X-mount camera adapter - a hands on review

The Metabones Speed Booster is an intriguingly novel product. There are any number of adapters on the market for mounting a DSLR lens to a mirrorless camera, but the limitation has always been that in doing so the practical focal length of the lens is altered. On an APS-C size sensor, like that in the Fuji X cameras, the lens focal length is multiplied by a factor of 1.5x, meaning that a 50mm full frame lens converts to a 75mm focal length on the smaller X sensor. The Speed Booster changes all that. With this adapter the focal length of the mounting full frame lens stays practically the same.  Even better, as a by product of the conversion,  the maximum lens aperture of the lens increases by one full stop so that the maximum aperture of a f/2.8 lens, for instance, would become f/2 when using the adapter. Sounds like a photographer's holy grail -- one that definitely piqued my interest enough to give it a try.  

To accomplish this miracle of conversion, the adapter must introduce an optical element within the lens to camera path, and therein lies a cause for concern. Any time an optical element -- no matter how well it is designed and manufactured -- is inserted between a lens and the camera some degradation of the image will usually take place. It might be slight, but it will be present. The best scenario would be when a camera manufacturer designs a specific device for one of its own lenses, as would be the case of Nikon designing a tele-converter to take into consideration the specific design of its own lenses and cameras. But even here, the rule follows that the insertion of any external optical elements into the path of lens-to-camera will compromise the optical quality of the original lens design to some degree. In the case of the Metabones Speed Booster the question becomes: Can it perform its miracle of conversion with a minimum amount of interference to the original design of the lens so the end product remains within acceptable limits. Let's have a look.

You be the judge.  I performed many tests with a wide variety of some of the best Nikon lenses, and included plenty of downloadable high res versions of my test images below. Take a look at them and judge the technical results of the Speed Booster for yourself. 

I choose to mount the Nikon G version of the Speed Booster on a Fuji X mount camera, but other adapters are available to mount the Nikon lenses on Sony E mount and micro four thirds cameras.

My X-Pro1 sure looks pretty impressive all decked out with Nikon's 80-400mm zoom mounted on it via the Metabones Speed Booster adapter. 
When I first began this hands on testing series I was mounting the Speed Booster on common focal length Nikon lenses, but it quickly became apparent that this was not very practical. After all, why use a Nikon lens interpreted through an auxiliary optical device, when a similar focal length Fuji lens of exceptional optical quality already existed. And so I realized that the Speed Booster would be most practical if it could convert lens types that were not available to the Fuji X-series APS-sized sensor. Throughout these tests I used the Metabones converter on all types of Nikon lenses, but paid articular attention to those focal lengths and lens types that were not otherwise available in a Fuji X-mount, such as the Nikon 80-400mm zoom, the Defocus Nikkors, tilt-shift models, and, yes, even the Nikon 16mm fisheye.

The Speed Booster shown here mounted on a Defocus Nikkor 105mm lens with a Nikon 16mm fisheye nearby.
The device is called the "Speed Booster" because a by product of its reducing the image size to fit onto the smaller APS-C sensor of the Fuji X cameras is that the amount of light is also increased proportionately so that the maximum aperture of the lens is increased by one full stop. For instance, a lens with an f/2 maximum aperture, would become the equivalent of an f/1.4 lens when mounted on the Speed Booster. That is a nice plus.

The Speed Booster does not transfer any of the Nikon lens data to the Fuji camera. Consequently, auto-focus on a Fuji X camera is not possible. The latest Fuji firmware update did improve the manual focusing system on the X-Pro1, and I found it to be quite helpful in acquiring a sharp focus.

The Metabones Speed Booster is 1 1/4" deep, and weighs in at a hefty 7.4oz (210g).  The aperture on Nikon G lenses is controlled by turning the numbered ring shown in the two photos above.
The adapter has its own tripod foot that is adaptable to the Arca Swiss style tripod mount. .
I did stick to the better quality Nikon lenses for my test, figuring that if the Speed Booster wouldn't work well with these, it certainly wouldn't perform well with consumer lenses. In general I found that performance with primes was better than with zooms, and better with long zooms than short zooms. This is to be expected. Short zoom lenses are very complex optical systems. Introducing another lens element into the light path is asking for trouble. 

The Speed Booster does have aperture control for the Nikon G lenses, such as the 50mm f/1.4G lens mounted on it above.
The two sample images below were taken using prime lenses, the Nikon 50mm f/1.4G lens for the top photo and 35mm f/2 lens for the bottom image. Both show good resolution when used with the Speed Booster.

Click here to download a high res version of this file.  

Click here to download a high res version of this file. 
One lens I tested was the Nikon 24-70mm f/2.8 zoom. This is one of Nikon's better zooms. The results are shown in the two photos below. Here you can see that at the longer focal length the results are acceptable, but when pulled back to 24mm the results were very poor, showing extensive vignetting and fringing.

Click here to download a high res version of this 70mm file.
The image above and below were both taken with the Speed Booster and Nikon 24-70mm zoom. For the photo above the lens was racked out to 70mm. For the bottom photo the lens was set to 24mm. Note that at the shorter focal length there is considerable vignetting and also some corner fringing.

Click here to download a high res version of this 24mm file.
I did a brick wall test with the 24-70mm zoom set to a mid range. You can download the test images below and judge for yourself. The center of the images was sharp at all apertures, but I continued the tests down to f/11 and still had considerable corner softness and color fringing.

This resolution test was done with the Nikon 24-70mm zoom on the Speed Booster. You can download the various aperture test images below.
Use the links below to download the high res samples of aperture tests of the brick wall test. You will notice that even stopped down to f/11 there is still considerable softness and fringing in the corners.

Click here to download f/2.8 high res sample.
Click here to download f/4 high res sample.
Click here to download f/5.6 high res sample.
Click here to download f/8 high res sample.
Click here to download f/11 high res sample.

The portrait test below was done with the Nikon 70-200mm f/4 lens mounted on the X-Pro1. It is shot against a very strong late day setting sun producing low contrast and considerable flare -- a tough situation for any lens. The resulting image is acceptable but lacking in contrast. When I shot the same portrait later with the lens mounted straight onto a Nikon camera, the resolution and contrast were much sharper.

Click here to download the high res version of this file.
For the series of tests below, the Speed Booster was mounted on Nikon's new 80-400mm zoom set to different focal lengths and distances. In general, all of them are just a tad softer than I would expect from this lens when it is used alone. Because this was a test, I didn't do anything to improve the sharpness. I do think all of these images would actually produce quite acceptable results with some very minor post-processing work. Fringing in any of the images was easy to deal with when bringing the RAW image in with Adobe Bridge, and resolution could have been improved with the addition of increased clarity, also in Adobe Bridge.

Click here to download the high res version of this file.

Click here to download the high res version of this file.

Click here to download the high res version of this file.

Click here to download the high res version of this file.

The Metabones Speed Booster is a new concept of lens adaptability in the digital age, and one that is exciting for those of us who would like to extend the range of systems like the Fuji X cameras to take advantage of some of the better, and rarer optics already found on full frame cameras. The system is not perfect. On the Fuji it is manual focus only. Thankfully, Fuji improved its focus peaking and extended it with the latest firmware update. At least manual focusing is now easier and more accurate.

As already mentioned, optical quality will be degraded somewhat simply by inserting another optical element in the image path. Nonetheless, the center sharpness with almost all lenses I tested remained very high. It is only in the corners that things began to fall apart, as the image softened, vignetting increased, and color fringing crept in -- all of which was more apparent with zoom lenses than with primes, and most of which was easily corrected in post-processing.

This is an expensive item.  A Fuji version costs $429. I suppose the price can be justified if you factor in the savings gained by adding a whole new arsenal of other lenses to the Fuji system. The Metabones Speed Booster means that over night my Fuji X-Pro1 becomes a more practical professional system with the addition of lenses such as my tilt-shift Nikkor. Of course why I would want to use such a lens on the X-Pro1 instead of on a Nikon full frame is whole other issue. I am not sure where a product like this will lead us. It is certainly intriguing, and begins to open new possibilities as the new mirrorless camera systems become more popular.

This detail photo was taken using a Nikon 24-120mm zoom mounted on the X-Pro1. Because it is a square crop this shot eliminates any problems that may have appeared in the corners. The resulting image is very sharp with good color and contrast considering it was a very cloudy day.
If you are planning on purchasing this adapter, you can help support this site at no extra cost to you by purchasing from one of our affiliate sellers listed below -- and thanks for your support.

Metabones Nikon G Lens to Fujifilm X-Mount Speed Booster can be ordered from:  BH-Photo   Amazon


  1. Is this thing at all compatible with AI/AIS MF lenses? And if it is, what's the trade-off?

  2. An f/2 lens with mounted Speed Booster will not become f/1.4 lens, it will remain f/2 lens. That is the fact of life and physics.

    1. An f2.0 lens will have a physical aperture of f2.0 with a light transmission of f1.4. I'd like very much to buy both Nikon g to m43 and C/Y to m43 Speed Boosters. Too bad in Europe we must pay 150$ apiece... Poor, if not any, distribution here; this is a Metabone's fail.

    2. I meant 150$ _more_ per each, sorry.

    3. http://www.metabones.com/images/metabones/Speed%20Booster%20White%20Paper.pdf

    4. "An f/2 lens with mounted Speed Booster will not become f/1.4 lens, it will remain f/2 lens. That is the fact of life and physics."

      "An f2.0 lens will have a physical aperture of f2.0 with a light transmission of f1.4."

      Well, I'm afraid that both these statements are wrong! The combination of an f/2 lens and Speed Booster DOES indeed become a physical f/1.4 lens, because the focal length is reduced (the actual, physical focal length, not some crop/effective concept) by 0.71x, while the physical clear aperture of the entrance pupil remains the same. The f-ratio is defined by [focal length] divided by [entrance pupil diameter], so f/2 drops to f/1.4.

      Take it from me, I'm an astronomer/optical physicist...we've been doing these sorts of simple calculations for a couple of centuries :)

  3. I have been interested in scaling down. I have a host of Nikkor lenses, but also 4 Zeiss lenses--a 24, 35, 50, and 100 mm. What do you think of a Fuji X-pro1, the Speed Booster, and the Zeiss glass as a compact kit?

    TIA for any "adult supervision"!


    1. I hear you, Mike. The older I get, the less gear I want to carry.

      The X-Pro1 is a sensational camera, but using the Zeiss lenses, particularly the wides with it is going to compromise their quality somewhat, especially on the edges. I'd be more inclined to use them with a straight through adapter. That way the 24 becomes 35, the 35 becomes 50, the 50 becomes 75, and the 100 becomes 150, and the lenses are still working at their optimum resolution.

      Then you could add just one lens, either the Fuji 14 or Zeiss 12, to cover the widest angle. If you don't need something as long as a 150, you sell that to help cover some of the cost of the 14 or 12.

    2. Thanks so much, Tom.

      Your review of the SB was a real education, both in terms of the SB, the X-pro1. I was ignorant about the existence of adaptors, and I am ecstatic about the possibility of putting my Zeiss lenses to use, as well as saving money for new glass.

      Do you have any recommendations for a "straight through adapter"? B&H carries one by Novoflex (a brand I've never heard of, for a price close to the SB): http://www.bhphotovideo.com/c/product/888375-REG/Novoflex_fux_nik_Adapter_for_Nikon_Lenses.html .

      Again, I appreciate your help, and I will stay tuned in to your blog.


    3. Mike, Novaflex adapters are well made, but verrrrry expensive There are of similar adapters available on ebay for a fraction of the cost. Just search on "adapter nikon fuji x". Keep in mind that this type adapter is manual focus only (including the Novaflex). Since you menitioned you want to convert Zeiss lenses, they are already MF so it shouldn't matter. One thing to look out for: Some adapters work with Nikon G lenses while others do not. May not be a problem for you if you don't have a G lens, but something to keep in mind. I have one of these G adapters for my Fuji and also a Leica R adapter. They work fine because they are really such a simple mechanism.

    4. I have Kipon brand adapters for Nikon G and Leica M. Not too expensive and so far I've had no issues with them. Decently made. Works fine.

  4. The f number is a ratio defined as the focal length of the lens divided by the aperture diameter. The speed booster decreases the focal length. With a constant maximum aperture, the wide-open f-number is decreased.

    So to the other anonymous, the stupid one, the f-number is not the "physical aperture." It is a ratio. You must be a Republican 47%er, a fine example of what's making the USA swirl down the toilet vortex.

    1. Ah, I see now that you got there ahead of me...I'm the astronomer/optical physicist who posted above.

      We made exactly the same point on the optics - except I managed to not be insulting (even if I do feel the same way about US Republicans :) )

  5. i don't get it . Fiji X -system is all about losing weight and bulkiness of equipment . Why should I combine the bulky lenses of an other brand such as Nikon or Canon as the lenses of Fuji ar at least equal in qaulity ?
    The Bokeh is even better ( for me anyway ) .
    but most of all i don't have to by me a mule to carry al te stuff .

    1. I agree it may seem ridiculous to put a massive lens on such a small camera, but it adds to the versatility of the system. I use an adapter - not the speed booster but a Kipon Brand plain adapter - mainly with an old Nikon manual focus 100mm F2.8 lens, which is a great lens and around a similar size to Fuji's 35mm 1.4. I therefore get an excellent 150mm equivalent telephoto lens at a very portable size. As I already had the lens and was using it on my SLR's, makes perfect sense to be able to use it on the Fuji also.

  6. you really miss the point of this device , and ask too much od it by paring it with unusual primes and zoom lenses

    try it with a fast 85mm 1.4 like the amazing and cheap korean rokonon with great bokeh iq , unbelievably soft creamy bokeh for such a budget optic

    and see a beautiful ff frame bokeh experience truly , at f1 no less!! hello

    even paired with a cheap 50mm 1.8 nikon af, the metabones sings a ff experience with very good iq better than the iq of the 50mm on apsc in a hollow adapter .... look into it ... its the delicious creamy bokeh experience of full frame that is this devices raison d`etre

    looking for sharp edges ?... for goodness put down the legacy lenses and use a good fuji x prime at f 4 or 5.6 ......just sayin :)

    and thank you for a fun read , none the less

    paul in nyc

  7. Hey, Paul, you make some really good points. Thanks for sharing. - t

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