Metabones Speed Booster – An Unbelievable Adapter

This is the new Metabones Speed Booster EF to E Mount adapter, and it’s mind blowing. You probably wouldn’t expect that from a lens adapter, but then again, you wouldn’t expect an adapter to give your lenses a 1-stop speed boost, a wider field of view, and a sharper image. Yep, you heard it right. Here’s a quick video review:

When the prototype arrived at my doorstep I was eager to see what had changed. When I opened up the package I noticed a lens element in the middle of the adapter…then I saw the words “Speed Booster” printed on the adapter. Still pretty clueless, I popped it on my FS100, put on my 50mm 1.4, and noticed something strange—the FS100 was reading the f-stop at an ƒ1.0. A mistake I thought, this is a ƒ1.4…But then what was all this about a ‘Speed Booster’ and a lens element? There was no documentation on or in the box, but this is a prototype and a very niche product, so that’s understandable. I contacted the company immediately asking for documentation or a manual. I was given the white papers, and there it was: “The Speed Booster: Increasing the speed of photographic lenses.”

Turns out that they’ve designed an integrated ‘focal reducer’ to their NEX lens mount adapter. It’s basically a reverse teleconverter. What does this mean? Well, like they say, it truly does increase the speed of the lens, technically. Why now and not…since the beginning of time? Well, a lot of things have changed lately that let this technique exist. Metabones notes the 18mm flange distance in the FS100 (distance from the mount to the sensor) is much shorter than typical cinema cameras that came before it. Also, using EF lenses meant for 35mm still photography will work just fine with the .71% adjustment, considering the FS100’s super35mm sensor.

It seems like everything aligned perfectly for this thing to be engineered by some really smart folks, and it’s definitely going to pay off. When I first threw the Speed Booster adapter on, I could instantly tell the difference in depth of field. an ƒ1.0 is very, very shallow. You may be thinking, “Well sure you can throw glass behind glass, but the sharpness of the lens will be lessened because of a whole lot of aberrations and what not.” After doing some test, I can confirm that this adapter appears to not only give you a speed up on your f-stop, a wider field of view, but it actually makes the images sharper. The white papers go into extreme mathematical detail about the MTF actually improving because of the speed booster. I’m no mathematician, so I had to just see it for myself. And I did, and it’s awesome.

So, just to review what we’ve got here…it’s an EF to NEX adapter that draws power from the camera, allows you to use your Canon lenses, actually makes those lenses FASTER, gives you a wider, almost full-frame field of view, and also makes the image sharper. This adapter will most likely go on sale January 14th, and be around $600. I can not for the life of me think of why every FS100 owner using EF lenses would not purchase this thing as soon as humanly possible. Metabones, thanks for letting me review your prototype, and good luck with the boat load of cash you’ll be making. Oh, and can I get one of these to keep, ASAP?

For more info, check out Metabone’s white papers on the Speed BoosterPhilip Bloom’s fantastic post, and visit to purchase this bad boy!


Update 1-28-13: Check out this VERY rigorous test of the Speed Booster over at! They really get into the nitty gritty, and the Speed Booster still holds up well.

Update 1-15-13: I shared this on Vimeo via the comments section, but I figure it could help others wondering if they should just go with this one adapter or the other.

I’ll be keeping both in my kit…I value everything that this new adapter does, but I just couldn’t see cutting out the other adapter. I could see wanting to have the crop at times, and also I’d like to use my EF-S lens (the Tokina 11-16mm) and any other EF-S lenses I might rent/buy. I think it’s important for people to keep that in mind.

Also, I always carry two adapters with, in case one fails (never happened, but you always need a backup).

Update 1-14-13: Regarding EF-S lenses, while they might not all work, here’s an example of the Tokina 11-16mm ƒ2.8 (the only EF-S I own). As you can see, the 11mm does vignette (no surprise), but the image is usable zoomed out at 16mm. I’d say around 14mm is safe for seeing little to no vignetting, so it’s not a complete loss.