Metabones Speed Booster Lens Adapter Review – LensRentals

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There’s a lot of buzz out there right now about the new Metabones Speed Booster Lens Adapter, and understandably so.  After all, the Speed Booster adapter promises to not only let you use your legacy lenses on a Sony NEX Camera (with other options available soon, including micro 4/3), it also promises to make those lenses brighter and faster (by a full f-stop) essentially, as if by magic, converting your small sensor camera into a full frame monster.  This almost sounds too good to be true…  but is it?

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Metabones Speed Booster Lens Adapter

The Metabones Speed Booster is now getting into the hands of reviewers who are putting it through it’s paces.  We’ve already posted an excellent reviews by Philip Bloom (the video above is one of the tests from Philip’s evaluation) and EOSHD, and now the latest evaluation comes from LensRentals, who explain it’s function as follows…

“…this is an adapter containing optical elements and electronic controls that allows you to mount Canon EF lenses to Sony NEX cameras (other versions are planned for other lenses and cameras). The quick summary is the adapter is the opposite of a teleconverter.

A teleconverter spreads out the light leaving the lens so that only the center portion reaches the sensor. The result is the focal length of the lens seems longer (the image is magnified), but at the cost of reducing the amount of light (effective aperture) of the lens. The Speed Booster compresses the light leaving the lens onto a smaller image circle. This makes the focal length seem shorter and actually increases the amount of light reaching the sensor.”

LensRentals take the position of the skeptic, as well they should, and they go on to say that “marketing hype will be marketing hype and people who want to believe in magic will believe it – and be disappointed when the magic doesn’t happen.”  But after some more research into the science behind the Speed Booster and those who created it, LensRentals then states the following…

“Then I flipped over to Metabones’ white paper on the Speed Booster and spit coffee. The primary designer of the adapter is Brian Caldwell. If anyone could make optics do magic, he could. He designed, for example, the Coastal Optics UV-VIS-IR Macro lens, an amazing thing that is the gold standard for forensic macro photography. So I read the white paper carefully and it made perfect sense. The White Paper explained how:

  1. The Speed Booster introduces zero (none, nada) spherical aberration, even with an f/0.9 output. That’s amazing. The very complete graphics in the White Paper do show it adds a bit of astigmatism and distortion, though.
  2. Where teleconverters magnify lens aberration, a focal reducer would reduce aberations basically because it would shrink them.
  3. The adapter is physically smaller than a standard, non-optical EF to NEX adapter.
  4. Corner illumination is improved.

After reading the white paper, I became convinced that these things were true. And these are all good things.”

What follows is a thorough, in depth evaluation of the Metabones Speed Booster (would you expect anything less from LensRentals?), culminating with the conclusion below.

Here’s LensRentals’ Conclusion

I think it was pretty obvious that I came armed for battle, ready to slam this product as some marketing overhype. I was wrong less correct than I might have been. The Speed Booster does what they claimed it would do, much to my shock and surprise. It creates a wider-angle, greater aperture lens while retaining resolution and acutance.

It does increase astigmatism a bit, although I doubt this will cause anyone problems unless someone is trying to shoot landscape photography with it. It also seems to create some highlight blooming at very wide apertures. Again, nothing that can’t be worked around and probably not something that will be noticeable with anything but the widest aperture lenses.

It is going to take a while and a lot of people experimenting before we find out what combinations of lenses and cameras are awesome with it, which are fairly good, and which fairly bad. They won’t all be the same. But I suspect most of them are going to be pretty good. And this is going to be a very useful tool. 

Most of the little foibles I’ve seen (including the part about adapter tilt) really only apply to photographers trying to tweek every drop of resolution out of their high-resolution sensor. Video, even 5k video, is more forgiving of a slightly weak corner or a bit of astigmatism. (Read full review on LensRentals)

My 2 Cents

Until I can actually get my hands on one of these little beauties myself, the jury will remain out.  With positive feedback mounting from trusted resources like Philip Bloom, EOSHD and LensRentals though, the circumstantial evidence is compelling.  As good as this looks, it’s important to recognize that this is still new technology and there will undoubtedly be bugs that need to be worked out.  But the possibilities that are opened up by this new technology is nothing short of staggering and can be a game changer in the world of imaging.  Stay Tuned!


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