EDIT: Now with new “Bokeh Circles” tests….An adaptor which claims to make your lens, faster, wider and better! This is NOT an April Fool’s!

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ETHICS: I have no business relationship with either Metabone or Conurus. They asked if I wanted to borrow a new lens adaptor for review that was “revolutionary”. Naturally I said YES PLEASE! I am receiving no financial remuneration for this blog post nor do I ever for any review, the exception being for any products that are my “Signature Products” or who are made by one of my affiliates for example Zacuto or Kessler. You can read more about my ethics here.

EDIT 17th January. I have just finished some tests that I have done with the Speedbooster adaptor, the FS700 and that MIGHTY chunk of glass from Canon…The L series 85mm F1.2. Please remember these are just mine and James’ unscientific tests below so any purchase decision based on these are naturally at your own risk. Please do not blame any tester if you find you don’t like it. It’s unlikely but a disclaimer I say about any review. So much is subjective and what one person likes does’t guarantee someone else does! 


This truly is a beast of a lens. Heavy but beautiful. The images achievable from this are gorgeous. It’s also DAMN fast at F1.2. It’s lenses like this and the 50mm L series F1.2 that Metabones are using to say you can get that magical number of  F0.9 on the FS100/700/ E-mount cameras with the adaptor (although the camera itself only reads this as F1.0, as it cannot go lower in its software)

If any lens was going to push this adaptor, it was this lens. James doesn’t have one, and I wasn’t able to test this lens with the speedboosterer until tonight (when I REALLY should be taking a break as I am between two workshops here in Dubai), when I got my hands on an FS700 here (mine is at home). So how does it fare?

It actually did bloody well…at  everything except wide open, but that is not the fault of the adaptor…it’s the lens, as it does the same thing on a full frame camera when wide open (as you can see from the sample image on the 1DC below). Some people like the oval bokeh though! I don’t. I like my bokeh circular, and to get that  circle at more closed off apertures you need a lot of blades! 

The lens was never super brilliant at F1.2. There is always a cost to going so crazy wide open. When you pull focus wide open, that’s when it does look weird. Both on the Speedbooster and full frame, you see a sort of circular bowing…again this is a lens characteristic that goes when you drop down to F1.4, and it’s not an artifact created by the Speedbooster.

What is really interesting is how damn close the bokeh looks on the Speedbooster image compared to the full frame 1DC image…those circles are very similar size. Not quite as large maybe as the full frame…if not it’s damn close! 

So, after pushing it to the extreme with bokeh, then comparing it to the same framing using the normal Metabones adaptor by moving back (therefore compressing the background so you see less, basically what a telephoto does) and then seeing how it compared… for me, it proves it’s an incredibly valuable piece of kit…I can now use my lovely 24-105 F4 on my FS700 and it has the range similar to how it is on my 1DX…it doesn’t lose that important wide end.

I have tested quite a few lenses now, so has James and so has Bryant Nero. I will test my 50mm F1.2 when I get back as it has been in for repair (third time in a year!!)

I have read comments that people think it is expensive at $600…I really do find this astonishing. Incredibly astonishing. Just think about it for a second…besides the fact that the normal adaptor costs $400, this is just $200 more and all your glass gains a stop and becomes wider. This is for $600…try buying faster glass instead, wider glass and see what the price difference is – then you will appreciate how good a value this is.

There’s also been some confusion about how an adaptor could possibly change a lens’s f-stop.

It’s confusing because Metabones has created a more-or-less new concept in the realm of DSLRs (the research is not new, but it’s new to mainstream users), and they need to describe it in normal photographer lingo. The adapter does increase the light hitting the sensor. Think of it like a magnifying glass, focusing light from a broader area (full-frame) onto a smaller area (M4/3). The problem is that the normal way to talk about an increase in light is to talk in f-stops. An f-stop is technically a measurement of the size of the aperture, and the aperture affects light input as well as other factors.

Now, the Speedbooster does not physically open the aperture any wider than it normally goes, but it does increase the light input. There’s confusion because photographers are normally used to thinking that “light input” and “f-stop” are two words for the same thing. They are directly related (they mutually affect each other), but they are not equivalent.

If you are familiar with cinematographer’s terminology, you might say that the Speedboster increases the t-stop , while the f-stop remains constant. t-stop is a pure measurement of light input, rather than aperture size. Hopefully that makes sense!!

Below are frame grabs from my tests. So to explain what these are, I have captions underneath each one. I shot with the FS700 in three different ways. 

1: Speedbooster adaptor with 85mm 

2: Standard Metabones adaptor and 85mm without physically moving showing the change in the frame size

3: Standard Metabones adaptor and 85mm attempting to match frame size by physically moving back from the object

For comparison I used the Canon 1DC I have on loan (which I rather adore…just wish it wasn’t so crazy expensive!) and shot in the following ways. 

1: Full frame full HD with the 85mm

2: Super 35mm Full HD with the 85mm showing frame size change

3: 4k mode (a 1.3x crop)…why? Because it would be rude not to! 🙂

I have also done some frame grabs part way through focus pulls wide open and at F1.4 with both the normal and Speedbooster Metabones on, to show the issues caused by being wide open on the speedbooster.

For the match frames I have tried my best to match them up as close as I could…but I am tired..it’s late and forgive me if it’s a wee bit off at times! No attempt at colour correction was attempted and the ISOs between the FS700 and 1DC do not match exactly so don’t use the 1DC / FS700 grabs as a barometer for sensitivity….that was not part of this short test…I used the 1DC purely for the speedbooster test to see what a real full frame looks like.

Click on the image to see it native size.

FS700 Speedbooster 85mm WIDE OPEN
FS700 Speedbooster 85mm WIDE OPEN
speed boost F1.4 85mm fs
FS700 Speedbooster 85mm F1.4
FS700 Normal Metabones 85mm wide open MATCHED FRAME by moving backwards a few feet

FS700 Normal Metabones 85mm F1.4

FS700 Normal Metabones 85mm F1.4 MATCHED FRAME by moving backwards a feet


FS700 Normal Metabones 85mm same position as Speedboster shot to show crop. F1.2 wide open 85mm
FS700 Normal Metabones 85mm same position as Speedboster shot to show crop. F1.2 wide open 85mm
FS700 Normal Metabones 85mm same position as Speedboster shot to show crop. F1.4  85mm
FS700 Normal Metabones 85mm same position as Speedboster shot to show crop. F1.4 85mm


FS700 Normal Metabones 85mm same position as Speedboster shot to show crop. F2 85mm
FS700 Normal Metabones 85mm same position as Speedboster shot to show crop. F2 85mm
Halfway through pull focus with speedbooster and FS700 wide open
Halfway through pull focus with speedbooster and FS700 wide open
Halfway through pull focus with speedbooster and FS700 F1.4
Halfway through pull focus with speedbooster and FS700 F1.4
Halfway through pull focus with normal metabone and FS700 wide open
Halfway through pull focus with normal metabones and FS700 wide open
Halfway through pull focus with normal metabones and FS700 F1.4
Halfway through pull focus with normal metabones and FS700 F1.4
Halfway through pull focus with 1DC in full Frame, full hd mode 85mm F1.2
Halfway through pull focus with 1DC in full Frame, full hd mode 85mm F1.2


1DC 4k mode (1.3x crop) wide open
1DC 4k mode (1.3x crop) wide open
1DC Super 35mm mode F1.2
1DC Super 35mm mode F1.2
1DC Super 35mm mode F1.4
1DC Super 35mm mode F1.4
1DC Super 35mm mode F2
1DC Super 35mm mode F2

Screen Shot 2013-01-22 at 01.12.54


I have been using the Canon EF to E mount adaptor from Metabones / Conurus since they released them last year. They were revolutionary, as they were the first Canon to E-mount that interfaced with your camera. The iris was controlled via the camera, the adaptor was powered by the camera and IS also worked. It’s compact, cheap and works…not on every lens – the odd one did strange things, but version two is a big improvement.

At the beginning of the year, I was emailed by them asking if I wanted to borrow and test out a revolutionary new lens adaptor for EF to E mount. I said yes but to be honest, I couldn’t imagine what could be revolutionary about another one of their adaptors…ND maybe? I then received it. I was puzzled, as it looked the same but had glass at the lens side, not open like the current one. How could that be a good idea, and what does it do. Not long after that I found out via another email with an attached white paper. It was called the “Speed Booster”. What on earth is a speed booster?!? I skimmed through the rather technical white paper and realised that this was no a job not for me, but for my right hand man, founder of Mensa (probably not true), the UK’s McGyver and all round great fella, James Miller who is frequently to be found down on Brighton Beach lens whacking. He does love to whack.  You can see loads of James’ Work on his vimeo page here.

James borrowed the adaptor for a few days and took the white paper to find out if what they claimed to be trued could be true. An adaptor that turns your current Canon/ Nikon lenses (no EF-S or DX) and makes them faster, wider and better optically. Wild, crazy claims and if true, clearly beamed to us from the distant future! Also, in reference to the blog title, a great one for an April’s Fool blog post. It’s just about 3 and a half months too early for that! So over to James to figure this out for all of us!


METABONES | Speed Booster by James Miller



Speed Booster Main



What is the Metabones ‘Speed Booster’?

In a nutshell, it makes your lens faster, wider and sharper! Yes, really. Have a look at the film and tests below to judge your self.

It really is that good!

Shot and edited in a few hours from inside my car (it was raining). Tripod on the passenger seat. Filmed along Brighton sea front on the South coast of the UK and over the Sussex Downs. It’s a really quick test filmed on the Sony FS100 over-cranked in camera. The lens used was the Canon 17-40mm f/4 lens. Shot at 24mm to crop out the window frame. I really just wanted to test to see if the adapter was usable. I would have done more with other lenses if I had had more time. Hopefully I can do this soon. More shooting details on my Vimeo page. – https://vimeo.com/57284024

My thoughts so far.

Does it work? Well yes. After what has been some very speedy non scientific tests, I am very happy with the images produced so far. From what I have seen, will I be ordering one on release? Again yes, yes I will. The adapter I’ve tested is a prototype, so final judgment should be reserved until a production version is used and tested. I love that I can have a real 50mm on the FS100. I really hope that Black Magic Design work out a live (electronic) M4/3 mount on their BMCC so I can use ‘IS’ lenses. It’s not going to bring the image up to full frame, but it will really help on lens choice. Of course, I would actually have to be able to get a camera first. But in hopes of a live M4/3 lens mount, this really does do away with the need for the EF mount version of the BMCC.

How is this possible?

I have no idea, but I think it might go something like this…

In essence, it’s an optical adapter that attaches to the E mount of a Sony NEX camera (Super 35 sensor) and then to a full frame SLR lens. The Metabones ‘Speed Booster’ is a 0.71 x focal reducer, that will effectively turn your full frame 50mm f/1.8 lens into a 35mm f/1.2 lens. Note, doing so (as a guide) will increase the aperture of that lens by one stop. Your Sony NEX Super 35 E-Mount will effectively have near full frame coverage on a full-frame lens. It also serves ‘double-duty’ as a lens mount adapter, from Canon EF lens (but not EF-S) to Sony NEX, with auto-aperture and image stabilisation.

It’s not just for really fast lenses – for example, a Canon 17mm f/4 TSE now becomes a 12mm f/2.8 ultra-wide tilt shift. I myself am still building a lens collection, and whilst the super fast Canons due to cost are not in my personal arsenal, my slightly slower Canons and Nikons have just been given a speed boost. That’s great news.

Speed Booster fig1


The above 2 images are shown with the Metabones Speed Booster note the lens bokeh wide open.



The above 2 images are shown without the Metabones Speed Booster.

Set up lit with 2 x 100w dedo lights set at 1 click on the box and a FilmGear LED Flo Light to the right of frame. Lights supplied from Jon at Shoot Blue. Sorry that it had to be booze in the shots, not much imagination! It was late, but I wanted that classic www.dpreview.com bottle of Baileys for resolution 🙂 What’s nice is the Bokeh remains the same – it just scales down in proportion to the image. That was one area I was worried about, but it’s great.


How does it increase the speed of the lens?

By the same way that a telephoto adapter decreases it. The ‘Speed Booster’ is placed behind the lens, so the entrance pupil of the lens (the aperture you can see when you look through the front of any lens) remains the same, but the focal length is reduced as it compresses the image, so the speed increases. (I think!) The amount of light that would have covered a full-frame sensor is now focused onto the smaller M4/3 sensor and is therefore more “concentrated”. There is a maximum input aperture of f/1.26 and a maximum output of f/0.90.


Why can’t the ‘Speed Booster’ be used on traditional DSLR’s like the Canon 5Dmk3?

Essentially the design is not possible, due to the flange distance (back of the lens to the sensor or image plane) and the reflex mirror. But with such an array of short flange distant mirror less cameras today, the opportunity is here to design an ‘inverse’ teleconverter. The benefits of the ‘Speed Booster’ come from taking advantage of full-frame lenses that are engineered to cover a much larger sensor than M4/3. This principle only applies when you have a lens that’s designed for a bigger sensor than the one you’re actually using.

This version is of the ‘Speed Booster’ is optimised for the NEX so it’s not just a case of putting it in a different housing. But the good news is that Metabones plans shortly after initial release, other camera mounts will follow, the Micro 4/3 and the Fuji X-mount and others in the future. That has some exciting possibilities! for the Micro 4/3 Black Magic Cinema Camera and the Panasonic GH3 and may also lead to the Canon EOS M series mount among others. Hopefully, Black Magic will at some point release the Micro 4/3 version of their Cinema Camera with live lens support.

Screen Shot 2013-01-02 at 11.08.12

Screen Shot 2013-01-10 at 07.38.06

What lenses can be used with the Metabones ‘Speed Booster’?

*All full frame 35mm SLR lenses. As they meet the coverage requirement of 40mm diagonal format covering 43.3mm. Speed Booster FX DX

Illustration show the relationship with Full Frame 35mm Lenses (FX) and lenses designed for crop sensors (DX)


Does the optical performance of the lens decrease when used with the ‘Speed Booster’?

It’s easy to assume it would, as you are all aware that teleconverters adapters basically will magnify the aberrations of the given lens.

The reverse is true for the MetaBones ‘Speed Booster’ as it compresses the image and reduces lens aberration for the given lens. Of course, the adapter is not completely aberration free, but still taking this into account, there is a significant improvement in MTF compared to the given lens used without the ‘Speed Booster’.

All other aberrations, including field curvature, coma, astigmatism, distortion, and chromatic aberration are also well-corrected.” Wow that is a big claim.

If you want to know a little information on what MTF (Modulation Transfer Function) is and how it’s measured here is a quick overview. – http://www.photozone.de/mtf

SpeedBooster_grab5 SpeedBooster_grab6

NoSpeedBooster_grab7 NoSpeedBooster_grab8

SpeedBooster_grab9 NoSpeedBooster_grab10

SpeedBooster_grab11 NoSpeedBooster_grab12

Will I still need my Metabones EF to E Mount adapter?

Yes, whilst it is fantastic to have the Metabones ‘Speed Booster’ focal reducer, you are also going to want your lens at the increased focal length you get on cropped sensor cameras. So by using a combination of Metabones adapters on my FS100, a 70-200 covers 70-200 at f/1.8 and up to 300mm at f/2.8.

SpeedBooster_grab13 NoSpeedBooster_grab14


Further advantages are lens size. It’s very hard if not impossible to find a lightweight, small, fast 35mm lens. But now by using the lovely cheap as chips 50mm f/1.8 Nikon E Series pancake lens, I can have a light weight small 35mm 1.2 that has increased MTF!! Brilliant.

Speed Booster comparison


I have the Nikon 50mm f/1.8 E Series lens. It’s a lovely light pancake and is well worth having in the bag. It’s the first lens I put on this adapter and for what it is, it’s great. They go on Ebay all the time. A good carry round lens with this adapter on a Sony 5n, 6 or 7.

Can you remember the cult lens used by NASA in the Apollo Moon-landing program? And the lens used by Stanley Kubrick in the film “Barry Lyndon”? It was the Zeiss 50mm f/0.70 this too used an integral focal reducer. Kubrick wanted to keep the scenes in Barry Lyndon as the eye sees them, natural without the need for additional fill lighting. He wanted candle lit scenes in English castles, lit by only the light of the candles themselves. To get wider shots, Kubrick also modified the lens further using an additional front mounted adapter from the Kollmorgen Corporation to produce a 36.5mm lens that remained at f/0.7.


zeiss50_07  NASA

Additional information from the White Paper:-


Fastest Lenses Available: There are only a handful of production lenses that are f/1 or faster, and even the fastest are only f/0.95 (The Voigtlanders for M43 so it’s all relative) However, the Speed Booster can be combined with an f/1.2 SLR lens to yield a true f/0.90 combination with excellent performance.

Compact High Speed Lenses: 35mm f/1.2 lenses are available and can be used with mirrorless cameras via various mount adapters. However, these lenses are bulky and expensive. By contrast, the Speed Booster can be combined with a tiny inexpensive 50mm f/1.8 lens to produce a very compact and high performance 35mm f/1.2.

Ultra-Wide Lenses: As mentioned in Section 6 above, the Speed Booster can be combined with ultra-wide lenses such as the 8-16mm Sigma zoom lens to produce a record-breaking 5.6 – 11.2mm ultra-wide zoom for Micro Four Thirds.

Fast/Wide Tilt-Shift Lenses: Canon and Nikon have recently made major upgrades to their fullframe tilt shift lens offerings. The Speed Booster allows these phenomenal lenses to be used on mirrorless cameras without losing their field of view. For example, a Canon 17mm f/4 TSE now becomes a 12mm f/2.8 ultra-wide tilt shift for either the Sony NEX or Micro Four Thirds platforms. What’s more, the full range of adjustment in the tilt shift objective can be used even after the Speed Booster is attached.

This MTF behaviour turns out to be typical of most lenses when used with the Speed Booster, namely: 1) both the Sony NEX and Micro Four Thirds versions give a dramatic MTF enhancement near the centre of the image; 2) the Micro Four Thirds version is better than the original lens used by itself over nearly all of the Micro Four Thirds format; 3) in the outer parts of the field the Sony NEX version has slightly reduced contrast relative to the Micro Four Thirds version where their image circles overlap; and 4) the Sony NEX

8 version in the extreme corner of the NEX format has similar MTF to the original lens in its original image corner.


Using the Metabones Speed Booster for stills?

Of course the Metabones Speed Booster is not just for video, it also does a great job in the stills area, and what better way to test resolution? I though this would be the weak point of the adapter but that does not seem to be the case.

Below is a very quick test using a Sony 5n E Mount camera. Shot at 70mm on the Canon 70-200 2.8 IS II lens. It looks like it does a really good job overall. I have not adjusted the expected exposure between the shots to match. I would have to do a few more tests to get an idea of corner sharpness. Also would be nice to test adjusting the physical distance of the camera to the subject to get the same framing.

Sony 5n & 70-200 Canon still image using the Speed Booster.
Sony 5n & 70-200 Canon still image using the Speed Booster.
Sony 5n & 70-200 Canon still image without using the Speed Booster.
Sony 5n & 70-200 Canon still image without using the Speed Booster.
100% Crop Sony 5n & 70-200 Canon still image using the Speed Booster.
100% Crop Sony 5n & 70-200 Canon still image using the Speed Booster.
100% Crop Sony 5n & 70-200 Canon still image without using the Speed Booster.
100% Crop Sony 5n & 70-200 Canon still image without using the Speed Booster.


And the most important question of all. Can I lens whack with this adapter?

Yes, yes you can. My favourite lens to ‘Whack’ with is a 50mm, and I really missed that on the Sony FS range. To get the same coverage I had to sometimes use a 35mm and fast 35mm lenses are heavy or very expensive. It’s best not to use the best glass when whacking just in case you drop it! I can now have that same look and feel I get with the Canon DSLRs.

Has this technology been used before?

Not in this unique setup – as it says, it’s taken the event of mirror less cameras with smaller sensors to make this happen. Barry Green over on dvxuser mentions that “the Olympus 14-35 & 35-100 f2.0 zooms are just 24-70 & 70-200 lenses redesigned with focal length reducers”.

But these are integrated into the lens and custom made for each zoom. Although this is just speculation, as this has not been confirmed by Olympus.
Here is a link to the article. http://www.dvxuser.com/V6/archive/index.php/t-236415.html


The ‘Speed Booster’ designed by Metabones® and Caldwell Photographic jointly . The White Paper will be available on Metabones’ web site following the press release. http://www.metabones.com


When will the ‘Speed Booster’ be available and how much will it cost?

It will be available in January 2013 from Metabones’ web site http://www.metabones.com and its worldwide dealer network for US$599 / £372 plus shipping and applicable taxes and duties. (EDIT PHILIP: I expect it to go sale tomorrow around noon Eastern US time)


HUGE thanks to James for this.

My additional thoughts…

When I first understood what this did, it made no sense to my tiny brain. James has made it a hell of a lot clearer and from his tests and using it he was really impressed. James is not an expert on optics, he is a shooter…he is just way more clued up on the technical stuff than me…after all he did notoriously remove an OLPF from his brand new 5Dmk3…Crazy man! BUT, let me say this. James is VERY HARD to please. He is always whinging about something he doesn’t like about a camera or something. So for him to say he wants one is a big deal. Should you go out and buy one because of this post? That’s up to you. I never recommend buying anything on one person’s say-so. I have it here with me in Dubai and will do some additional testing…I have my 85mm F1.2 with me, so that should be lovely lens to test it out with.

Is it too good to be true? Apparently not, according to James. I will add more thoughts throughout week the more I use it. If it really is as good as it seems, this really is going to be an absolutely essential piece of kit for anyone with an E-Mount camera and Micro Four thirds cameras. If the upcoming Blackmagic M43 will have electronics on it and won’t be passive, then this will be the essential for that camera and will actually make it way more appealing than the Canon EF version and will solve so many issues we have with the sensor size. It’s not actually quoted on the white paper, but theoretically this adaptor “could” get those lenses to behave more like they were on a S35 sensor than the 2.3x crop, which to be honest would be fantastic. 

The reason that I say that I would want the BMD m43 to be electronic and not passive as it would then let us use Canon glass properly with this adaptor even though I mostly use Zeiss manual glass and without power it would work perfectly with manual glass. To have power would give us all that Canon glass with full control and most importantly IS…that rolling shutter needs IS for long lenses and handheld!

As it stands, just what it can do for S35 camera like the FS100 and FS700 is astounding. If only the Canon C300 and C100 didn’t have that stuck on camera mount…that’s the problem. It does wonders for Canon glass on other cameras…just not on Canon cameras! There is a fair bit of irony there! We now need one for the F3, F5 and F55!

I would love to see this in the hands of a true lens boffin to analyse for us. Hopefully this will happen soon. Then we can get some seriously tech analysis. For me and James we are more than happy. After all this is $600 not $6000!

My order for the production model will go in as soon as I can do it! I must say it’s rare for me to be utterly wowed by something but by jove I think I am. I need to test it more but so far my jaw is rather slack.

Oh and if you are in Dubai I do have the adaptor with me and will be doing a 1 day and a 2 day workshop this week, so do come if you can! Click the flier below for more info!