First Impressions: Metabones Speed Booster

The Metabones Speed Booster is shown here mounted on a Sony NEX-6 with a Canon EF 40mm F2.8 lens.

We've had the Metabones Speed Booster in the office for a few days and wanted to share some initial thoughts on the possibilities and challenges presented by such a unique product. While Metabones has announced plans to support a variety of lens/mount combinations, its first offering is a Canon EF to Sony NEX Speed Booster, so we put some Canon full frame lenses on our Sony NEX-6 and did some comparisons alongside the Canon EOS 6D we're currently reviewing. 

What is the Speed Booster?

As we reported recently, the Speed Booster is an adapter that allows for a full frame lens to be mounted on APS-C or Micro Four Thirds mirrorless cameras. There are two reasons why this is very big news, and both revolve around the optics inside the adapter. Firstly, Metabones claims that by reducing the image magnification, the Speed Booster gives an overall focal length multiplier of around 1.09x, promising a nearly full frame field of view on APS-C. The second claim, as its name implies, is that the Speed Booster increases the lens's speed by a stop, turning an F2.8 full frame lens into an F2.0 optic that allows for low light shooting at a lower ISO sensitivity.

This image was shot with the full frame Canon EOS 6D using the EF 35mm F1.4 L lens. The green crop illustrates the field of view when shot from the same position with an APS-C  Sony NEX-6 using the same 35/1.4 lens via the Metabones Speed Booster. The blue crop shows the native field of view of the NEX-6 if shot from the same position at the same focal length without the Speed Booster adapter attached.

How can an adapter change the focal length and aperture of a lens?

The Speed Booster is most easily understood as being the opposite of a teleconverter – in that it reduces your focal length. This, then, has a domino effect on the F-number of the lens. Because the F-number is the focal length divided by the width of the entrance pupil, reducing the focal length without changing the entrance pupil increases the F-number. So, adding the speed booster to a 50mm F1.4 lens turns it into a 35.5mm F1.0. But, since we’re then going to mount it on an APS-C camera, a comparison of this lens-plus-adapter combination to a full frame camera means we have to multiply these numbers by the camera's 'crop factor'. The end result is a 53.25mm equivalent lens that gives the same depth-of-field as an F1.5 lens would on a full frame camera.

The Metabones Speed Booster contains optics, designed by highly regarded lens designer Brian Caldwell, that match the image circle of a full frame lens to a smaller format sensor.

And, if making lenses faster sounds like witchcraft, don’t forget that when you normally mount a full-frame lens on an APS-C camera, it illuminates an area larger than the sensor. With the Speed Booster, rather than losing this light, you’re effectively condensing it all onto your sensor. Again, it's doing the exact opposite of what a teleconverter - which loses light - does. The end result is that in terms of light capture and depth-of-field - as well as field of view - your full-frame lens behaves essentially as it would on a full-frame body.

AF compatibility

The Canon EF to Sony NEX version of the Speed Booster supports autofocus. But before you get your hopes up, here's a quote from Metabones' own product page:

'Autofocus speed is very slow and inadequate for most moving subjects. The autofocus speed is unfit for professional use for sure, and it would disappoint most enthusiasts.'

Our experience confirms this. Essentially you need to think of the Speed Booster as a manual-focus adapter. Even in good light, you'll get much faster results by focusing manually, particularly on a camera like the Sony NEX-6, which offers focus peaking. This is not surprising if you think about it, as the adapter is mating a lens optimized for phase-detection autofocus (PDAF) to a camera that uses a contrast-detection autofocus (CDAF) system.

It's also worth noting that the Canon EF to Sony NEX mount model is currently the only Speed Booster version to support AF at all. And the choice of AF-compatible lenses is limited to Canon EF models introduced in 2006 or later. Older (and third party) lenses operate in manual focus only.

Optical performance

As you can see from the examples below, Metabones' claim of 'almost full-frame coverage' is no idle boast. We've shot our resolution chart using the same lens on both the NEX-6 with Speed Booster adapter, and the EOS 6D; each camera was shot with its sensor plane located the same distance from the resolution chart. Based on our image comparisons, we calculated a focal length multiplier of about 1.07x, which is virtually identical to the company's assertions.

Sony NEX-6 + Canon EF 50mm F1.4 USM with Speed Booster: 1/50 sec. F8.0, ISO 100 Canon EOS 6D + EF 50mm F1.4 USM:
1/50 sec. F8.0, ISO 100

The Speed Booster combines with the Sony NEX-6 to provide a slightly narrower field of view compared to the full-frame Canon EOS 6D. The raw files were processed in ACR 7.3 beta to match white balance and brightness, with all other settings, including sharpening at their defaults.

As the 100% crops below attest, the center sharpness performance of the Speed Booster is very impressive. You'd be hard-pressed to find significant difference between the two files in the center of the image, other than the slightly higher resolution of the 20MP Canon EOS 6D versus the 16MP NEX-6. In the second set of crops, however, taken from the lower left corner of the chart, you can see softer corner performance and more prominent chromatic aberration (CA) from the Speed Booster.

Sony NEX-6 + Canon EF 50mm F1.4 USM with Speed Booster. 100% crop Canon EOS 6D + EF 50mm F1.4 USM. 100% crop
100% crop 100% crop

With such impressive results, we thought it would be interesting to see how optical performance fares at a very wide aperture. The image below was shot with the same Canon EF 50mm F1.4 USM lens on the Sony NEX-6, and the Canon EOS 6D, but this time at an aperture of F1.4. Raw files were again, processed with ACR 7.3 beta.

Sony NEX-6 + Canon EF 50mm F1.4 USM with Speed Booster: 1/40 sec. F1.4, ISO 100

In the image above, you can see more obvious lens distortion at F1.4, as you'd expect. (Click the image for a full resolution version.) In the 100% crops below you can see that image quality suffers somewhat in the corner of the frame compared to the full frame EOS 6D.

Sony NEX-6 + Canon EF 50mm F1.4 USM with Speed Booster. 100% crop Canon EOS 6D + EF 50mm F1.4 USM. 100% crop (Click for full resolution image).
Top right corner: 100% crop. Top right corner: 100% crop.

We've also found that the Speed Booster introduces significantly more vignetting in image corners with the Canon EF 85mm F1.8 lens than you find on the full frame Canon EOS 6D, presumably due to a mismatch between the size of the lens's rear element and the Speed Booster’s front element.

Sony NEX-6 + Canon EF 85mm F1.8 USM with Speed Booster: F8, ISO 100 Canon EOS 6D + EF 85mm F1.8 USM:
F8, ISO 100

Still, you can't help but be impressed with the sharpness performance of the Speed Booster at an optimum aperture. And while vignetting, CA and large aperture corner performance are concerns, we must stress that 100% crops of test charts can overstate the practical implications of how the lens performs out in the real world. So we took the Speed Booster out of the testing studio for some shooting.

Real-world usage

Sony NEX-6 + Canon EF 85mm F1.8 USM with Speed Booster: 1/160 sec. F4, ISO 1600.  ACR 7.3 beta raw conversion.

There's no denying the pleasure of putting your SLR lens on a mirrorless body without significantly limiting your field of view, particularly with wide angle primes. And the ability of the Speed Booster to allow more light to reach the sensor should mean that you can capture equivalent exposures while shooting at an ISO setting that is one stop lower than using the same lens without the adapter.

Sony NEX-6 + Canon EF 40mm F2.8 STM with Speed Booster: 1/30 sec. F2.0, ISO 3200 Sony NEX-6 + Canon EF 40mm F2.8 STM with Speed Booster: 1/60 sec. F2.0, ISO 1000

In the low-light scenarios above, using the Speed Booster allows the Canon EF 40mm F2.8 STM lens to behave as an F2.0 optic, thus letting you shoot handheld at ISO 3200 and ISO 1000, respectively.

We did find, however, that shooting at the widest possible aperture (so F1.0 on a nominal F1.4 lens, for example) consistently resulted in a darker exposure. We found this to be true whether we allowed the Sony NEX-6 to meter the scene or set exposure manually. As you can see in the comparison below, maintaining an equivalent exposure between F1.4 and F1.0 actually results in a darker scene.

Sony NEX-6 + Canon EF 35mm F1.4 L with Speed Booster: Av mode, 1/500 sec. F1.4, ISO 100 Sony NEX-6 + Canon EF 35mm F1.4 L with Speed Booster: Av mode, 1/1000 sec. F1.0, ISO 100

The most likely explanation is not due to any flaw of the Speed Booster. Rather, with the phenomena known as pixel vignetting, in which at very wide apertures, the light gathering ability of the sensor's photosites diminishes slightly. If you've never heard of this, it's because characteristics like these are often corrected automatically in-camera based on the information the camera has about the lens mounted on it. And of course, this chain of information is affected with the use of the adapter. We want to stress, however, that on all of the EF lenses we've used with the Speed Booster it is only at the maximum aperture (enabled by the Speed Booster) that we've seen this occur.

Summary

There's a lot to be excited about with a product that so transforms lens behavior and addresses such a long-standing issue for photographers who long for the wide-angle and light-gathering performance of their older full frame lenses on their newer APS-C body. Image quality is very impressive, with results that compare exceptionally well against a full frame sensor. You do pay a small price in terms of corner softness and CA.

The biggest remaining challenge, however, with the Canon EF to Sony NEX mount is AF speed, a direct consequence of pairing a PDAF-optimized lens on a CDAF sensor. And to their credit, Metabones makes it very clear that AF performance is going to lag far behind what you'd get by using the Sony NEX's conventional AF system.

This does effectively make the Speed Booster an even more niche product, as it's best suited for manual-focus shooters. We'd be keen to see a camera manufacturer license this now-proven technology and offer this optical quality and near-full-frame performance mated with an effective AF system. But for now, we tip our hats to Metabones for releasing a product that accomplishes what many had thought nearly impossible.


You can follow Amadou Diallo on his Facebook, Google+, Instagram or Twitter feeds. Richard Butler shares insights on his Google+ feed.

Comments

Total comments: 355
123
johnmcpherson
By johnmcpherson (Feb 1, 2013)

I think that's what F1.2 lenses are for...
Give me a real SLR and a fast lens. I'll take quality over a gimmick anytime.

Comment edited 2 times, last edit 23 seconds after posting
3 upvotes
Cane
By Cane (Feb 1, 2013)

Ok old timer. There's only one way to do something, the old fashion way, right?

11 upvotes
marike6
By marike6 (Feb 1, 2013)

This adapter is not only about lens speed, but increasing FOV on crop sensor cameras, an interesting prospect to a large group of users.

2 upvotes
David Rossberg
By David Rossberg (Feb 1, 2013)

As mentioned before the real "gimmick" of this adapter (and it's predecessor) is the ability to mount quality glass on quality video cameras. In other works you do get quality over gimmick.

0 upvotes
Benarm
By Benarm (Feb 1, 2013)

Great and innovative niche product. Pretty sure that there will be many users who will make great use of this. For me, I'll wait for native FF NEX and improved on-sensor PDAF. :)

2 upvotes
marike6
By marike6 (Feb 1, 2013)

"Great and innovative niche product." Kind of a backhanded compliment.

0 upvotes
David Rossberg
By David Rossberg (Feb 1, 2013)

Why? Does it have to be great and innovative mass market product? Some of the most interesting innovations are niche products.

Also, niche products can quickly become very broad as the market adapts. Palm Pilot was a niche product but a few years later iPad is as mass market as it gets in the "electronic gadgets" segment.

0 upvotes
Jun2
By Jun2 (Feb 1, 2013)

"Essentially you need to think of the Speed Booster as a manual-focus adapter", not interested at the current price.

0 upvotes
Tom Caldwell
By Tom Caldwell (Feb 1, 2013)

That is a normal comment, "stand aside sir there is a queue forming behind you".

2 upvotes
Jason Rickerby
By Jason Rickerby (Feb 1, 2013)

Some of us have been using focal reducers/field flatteners for many years:
http://www.celestron.com/astronomy/celestron-reducer-corrector.html

Canon 20D with 2000mm - F10 optics, without reducer:
"http://www.pbase.com/jmrickerby/image/36793235/large.jpg

Canon 20D with 2000mm - F10 optics, with reducer; now effectively 1250mm - F6.3:
http://www.pbase.com/jmrickerby/image/46035713.jpg

Comment edited 2 times, last edit 2 minutes after posting
0 upvotes
intensity studios
By intensity studios (Feb 1, 2013)

I would definitely buy one when it makes it to $100-$200 price point.

As it is now, if you buy a mid range DX camera for $1000 and add this is comes out to about $1600, for which you could buy a low-end or used full frame, which would be better than an adapter.

But this item definitely could be useful for a lot of people. It just needs to hit the right price point. Remember, most people use DX because of limited budget, but to get your wide angles actually be wide would be very useful

1 upvote
viking79
By viking79 (Feb 1, 2013)

Or buy a used NEX for a couple hundred and the adapter and you are well under $1000, not much more than a used 5d MK1, but a lot less than a 5dII or D700. I am not trying to lean people one way or the other, I would rather have the full frame, but if you are going to compare a used full frame, might as well compare a used APS-C camera.

2 upvotes
Tom Caldwell
By Tom Caldwell (Feb 1, 2013)

I suggest that these things are for those with the more expensive lenses rather than a budget adapter. On the other hand where is a budget adapter for an EOS EF lens that doesn't insist on shooting wide open only?

0 upvotes
Timmbits
By Timmbits (Feb 2, 2013)

Isn't it ironic, that the argument being used, is that you can use those very expensive old lenses, that give you such amazing image quality, but to see that quality disappear? may as well buy that cheap new lens or two that was missing from your new camera arsenal, for the $600, and still have less CA and fringing than a great lens on a SB.

1 upvote
sportyaccordy
By sportyaccordy (Feb 1, 2013)

Good stuff

1 upvote
piratejabez
By piratejabez (Feb 1, 2013)

Personally I would be interested in a full frame to APS-C speed booster, allowing me to get the most out of my old full-coverage lenses on my newer, cheaper, crop-sensor DSLR bodies.

1 upvote
Tom Caldwell
By Tom Caldwell (Feb 1, 2013)

Technology cannot be used on any, repeat any, dslr body it needs the space otherwise used by the mirror.

2 upvotes
jlabate
By jlabate (Feb 1, 2013)

Since the autofocus is so poor, how about offering a simpler less expensive one without autofocus.

3 upvotes
Amadou Diallo
By Amadou Diallo (Feb 1, 2013)

Sounds reasonable, but unless you're willing to give up aperture control and IS activation, by avoiding all the electronics, dropping AF alone doesn't cut costs significantly.

Comment edited 2 times, last edit 1 minute after posting
6 upvotes
cyberstudio
By cyberstudio (Feb 1, 2013)

There is a Leica-R version for only 399, and 449 for Alpa. So, in fact, the non-electronic versions are significantly cheaper and much more affordable.

0 upvotes
Amadou Diallo
By Amadou Diallo (Feb 1, 2013)

Precisely my point. If you take out *all* of the electronics you can lower the cost. But you don't get a cheaper adapter just by eliminating AF.

Comment edited 2 times, last edit 1 minute after posting
2 upvotes
forpetessake
By forpetessake (Feb 1, 2013)

They have Leica-NEX SB, which doesn't have any electronics and is $200 cheaper.

0 upvotes
viking79
By viking79 (Feb 1, 2013)

But then you can't control the aperture in the Canon lenses. The Canon version has to have electronics.

3 upvotes
Tom Caldwell
By Tom Caldwell (Feb 1, 2013)

The autofocus works on some lenses but hunts. This is some problem awaiting to be resolved. But take away phase detect on a Canon camera and it might hunt-focus just as much. In fact some Canon lenses have a focus-range reducer switch to reduce focus hunting. In reality this adapter is a very sophisticated unit - it understands which Canon lens is mounted, records EXIF and adjusts the f-stop information inside the camera control to match the real life aperture. Maybe manual only but I have no problem with focusing and of course Sony provides focus peaking and good magnification to assist this. I don't think this is a device that anyone can expect "perfection" for a 20 cent tip.

0 upvotes
forpetessake
By forpetessake (Feb 1, 2013)

Those who were skeptical about the Metabones claims turned out to be right. The resolution, CA, vignetting, contrast do get worse, some may say unacceptable. The AF isn't really working, but manual focusing on EF lenses is poor, because the lenses were designed for AF and focusing rings are crude. It still remains an option between now and the time when FF NEX will be released. When the latter comes out, nobody will care about this adapter.

3 upvotes
cyberstudio
By cyberstudio (Feb 1, 2013)

The Metabones is "faster, sharper and wider" on the same camera body (i.e. NEX-6 vs NEX-6). Since that has already been widely recognized as fait accompli, no reviewer bothered to verify those claims, but they all go straight to see if we have a full-frame killer. Of course, we don't! (Why would anyone expect SB to be able to kill full frame?) But keep in mind Metabones themselves had never made that claim, it is just people setting their expectations unrealistically. The Metabones site said "Fully ultilize your full frame lenses on mirrorless camera today with Speed Booster." It did not say replace your full frame camera with SB+APS-C. Thanks to Dr Brian Caldwell's work, it is still a very impressive feat how close we get to full frame quality from an APS-C camera. Without a doubt, some people would want a full-frame DSLR but some people would want APS-C mirrorless + SB instead, so to each his/her own.

Comment edited 7 minutes after posting
6 upvotes
SergioNevermind
By SergioNevermind (Feb 1, 2013)

All the optics have been there sitting in your FF lenses, for the last 20 years.
But when DSRL came with their small sensors AND the same mounts to support older (bigger light circle) it was so obvious our hope NEW APS-C lenses should be the same but brighter ! .... Well if lens makers had took their FF lenses and just modified a little the inner design, the result would have been exactly the same but... WITHOUT ADAPTER, on any APS-C sized Dsrl you could have got same field of view and more light on new released lenses for the system.

But manufacturers went all the way back. Newer dedicated APS-C lenses were darker, and cheaply constructed.

It was just a little lens re- design required to make APS-C a goal, not a lens downsizing as they did.

This adapter comes to show how miserable companies have been in order to keep the high prices of FF cameras, not providing any capabilities to their APS-C owners.

Metabones just put light in the right spot. That's optics, not magic.

1 upvote
marike6
By marike6 (Feb 1, 2013)

@forpetessake said "It still remains an option between now and the time when FF NEX will be released. When the latter comes out, nobody will care about this adapter.

Tons of people will care about this adapter even after your hypothetical $2600 NEX FF comes out.

NEX shooters are a small percentage of APS-C users and there are m43 users in desperate need of wider FOV, faster lenses. Video professionals using the Black Magic Cinema Camera in m43 mount and GH3/GH2/AF101 shooters are doing backflips over this adapter and the prospect of wider, faster glass.

As far as pixel-peeping IQ, you wouldn't have had any idea the above real-world images were shot with an adapter. None. Yet now after the fact you're talking about "unacceptable" IQ because of slight aberrations only visible in 100% crops? Seriously?

Metabones deserves nothing but praise for designing and implementing this adapter.

Comment edited 3 minutes after posting
10 upvotes
noirdesir
By noirdesir (Feb 1, 2013)

I guess when you review a teleconverter you will also write that a 1.4x TC claims to increase the focal length by a factor of 1.4 and reduce the f-stop by one stop.

My point is, why do you talk about claims of this focal length reducer. They are not claims, they are simply specifications like the focal length of lens. You don't write that a 50 mm lens claims to have a focal length of 50 mm.

2 upvotes
Revenant
By Revenant (Feb 1, 2013)

Probably because, judging from many of the comments when this adapter was announced, a lot of people have trouble understanding how an extra piece of glass can make a lens faster, thus questioning the manufacturer's "claims".

4 upvotes
noirdesir
By noirdesir (Feb 1, 2013)

And using the word claim here lends support to the notion that doubting that such a thing like a focal length reducer can exist was not an unreasonable position.
And I don't know what lets me dispair more: (a) that so many people were unable to tell whether the announcement was a hoax or not or (b) that people couldn't apply simple logic and see that if a TC is possible, a reducer is also possible.

0 upvotes
marike6
By marike6 (Feb 1, 2013)

The first portrait's EXIF reports:

89mm focal length (35 mm Equiv) and max aperture f/1.3

Then under Image Properties - Focal length 59.50 mm

How awesome is that?

0 upvotes
Amadou Diallo
By Amadou Diallo (Feb 1, 2013)

Pretty awesome, @marike6. What's even better is when you rotate the aperture dial on your F1.4 lens all the way until you see F1.0 on the Sony LCD.

2 upvotes
marike6
By marike6 (Feb 1, 2013)

Stupendous!! By the way, the 85 1.8 image sure does look crisp. I used to have the EF 85 1.8 and it's a heck of a lens for the price. Nice job with the Metabones.

0 upvotes
Amadou Diallo
By Amadou Diallo (Feb 1, 2013)

Thanks.

0 upvotes
Holger Drallmeyer
By Holger Drallmeyer (Feb 1, 2013)

Not seeing it. Maybe it's Sony's sensor but it does look pretty bad from what I can tell here on the screen. A closer look is needed.

0 upvotes
DPReview Staff
By DPReview Staff (Feb 1, 2013)

For a closer look, click on the image and you can browse around at 100%.

7 upvotes
Airless
By Airless (Feb 1, 2013)

I would really like to see the Sigma 8-16mm lens used on an m4/3 camera to produce an 11.2mm equivalent focal length, the widest focal length in existence.

0 upvotes
cyberstudio
By cyberstudio (Feb 1, 2013)

Not sure but we may have to file away the integral hood a tiny little bit. Horizontally it will barely cover but vertically 4:3 is taller than 3:2 so there is a chance that the integral hood may get into the frame. This is explained on page 14 of the white paper.

0 upvotes
podchong
By podchong (Feb 1, 2013)

I'm Nikon uesr and having NEX-C3 for my lovely days photography.
If they would have F-mount speed booster for E-mount I will buy one.
Because now I like to upgrade my C3 to 5N or 5R and left my Nikon
only for my work. And I would like to having fun with my Nikon lenses
on my NEX.

0 upvotes
Dédéjr
By Dédéjr (Feb 1, 2013)

Maybe it is me or my rubbish laptop screen but... not impressed at all by the image quality here on show. Sorry no cigar from me.

1 upvote
Mssimo
By Mssimo (Feb 1, 2013)

This is a game changer in the video world. Combine the metabones with some samyang lenses and you got yourself a cheap mans Arri Alexa.

2 upvotes
marike6
By marike6 (Feb 1, 2013)

Good I've always wanted an Arri Alexa. Unfortunately I think just might be exaggerating a wee bit as there's more to the Alexa than it's Super 35 sensor.

0 upvotes
Mssimo
By Mssimo (Feb 1, 2013)

Maybe a bit, but you got the point ;)

0 upvotes
headofdestiny
By headofdestiny (Feb 1, 2013)

Super 35 sensors are essentially the same size as aps-c.

2 upvotes
wakaba
By wakaba (Feb 1, 2013)

Yep, and it shows in the theaters. Time to introduce 24k...

0 upvotes
DrugaRunda
By DrugaRunda (Feb 1, 2013)

Interesting product, will there be one in PK mount? I for sure would be interested to try it out.

0 upvotes
Freestyler
By Freestyler (Feb 1, 2013)

Yes it's called the Pentax K-01, this allows all of the PK lenses you wish on a 16Mp Sony Sensored mirrorless camera. ;)

0 upvotes
JohnBee
By JohnBee (Feb 1, 2013)

Less the FOV and available light gains.

0 upvotes
Freestyler
By Freestyler (Feb 1, 2013)

Yes but it has usable AF, and costs less than the adapter by itself, (not to mention the NEX and lenses) and doesn't make the edges softer. :P

0 upvotes
marike6
By marike6 (Feb 1, 2013)

Really well done report guys. Interesting and informative analysis of the Speed Booster, and your images from the NEX-6 with EF lenses look superb. Hmmm.

If Metabones has a F-mount version, I might have to order a cheap NEX-5N or D5100 and have a play with my Nikkor lenses. The only obstacle I see with that plan is the adapter costs as much or more than the DX bodies, but it's worth it. Great job, Thanks.

0 upvotes
Shamael
By Shamael (Feb 1, 2013)

Is it really worth it, if you have good Nikon glass, buy a D5200 body. The expansion from a dx format to FF size does not impresses me at all. You have good and well priced lenses for DX format, for the price of this adapter you get a Sigma 30-1.4 and a few cases of beer. Adapters are ok if they are good in quality and fair priced. I would not spend 600$ for an adapter that makes this bad AF performance. If Sony made this kind with AF and FF magnification and asked 300$, I would buy it, Anyway, all they need to do is add the magnifying lens to the LA-EA2 adapter.

0 upvotes
Total comments: 355
123