Video / Tips and Solutions

How to Emulate Super 35mm 4K Video with the Panasonic GH4

The Panasonic GH4's ability to record both DCI 4K and UHD video internally, without line-skipping or pixel binning, sets a new standard for in-camera video recording with HDSLR and mirrorless cameras. However, a potential drawback of this method is that the GH4 can only use the center portion of the sensor. This results in about a 2.3x crop factor when compared to full-frame cameras, as opposed to the typical 2x crop for normal Micro Four Thirds cameras, which puts the GH4 into slightly weird territory when it comes to using lenses. It’s smaller than normal Micro Four Thirds and larger than super 16mm, making native lenses hard to find. Luckily, there is one combination that ends up working really well: using APS-C or DX-optimized lenses with a Metabones Micro Four Thirds Speedbooster.

Update: A chart has been added at the end that compares the effective focal length of these lenses with a Speedbooster, to their 35mm equivalent focal lengthtaking into account the 4K crop you get with the GH4, and the changes in specs introduced with use of a Speedbooster.

"One combination that ends up working really well: using APS-C or DX-optimized lenses with a Metabones Micro Four Thirds Speedbooster."

Normally, when you mount a lens designed for a larger sensor on a camera with a smaller sensor, all of the light that doesn’t hit the sensor is unused. However, the Metabones Speedbooster concentrates the light entering the lens into a smaller area, which virtually decreases the focal length and increases the aperture on the smaller sensor. The Nikon G to Micro Four Thirds Speedbooster reduces the focal length of the lens and the lens circle area by a factor of .71, which also increases the apparent aperture by one stop. For the typical Micro Four Thirds camera with a 2x crop factor, a .71x reduction reduces the image circle to a slightly smaller area then APS-C optimized lenses are designed for, effectively a 1.42x crop factor, while APS-C lenses are designed for a 1.5x crop factor. Some lenses may work, but others may present a little vignetting. However, when shooting 4K video on the GH4, it works out nearly perfectly. The field of view will be almost identical to having an APS-C camera, as the overall crop factor with the Speedbooster while shooting 4K with the GH4 is about a 1.6x, nearly identical to APS-C still or Super 35mm cinema cameras. At this time, there is only a Nikon to Micro Four Thirds version of the Speedbooster available, so this article will focus on lenses that are available for Nikon Cameras.


Below is a list of APS-C optimized lenses that will make a great option for shooting 4K video with the Panasonic GH4, when paired with the Metabones Speedbooster.

Wide-Angle Lenses

Shooting wide is one of the more difficult aspects of dealing with crop factors that lack native lenses. The widest-angle lens available natively for Micro Four Thirds is a 7-14mm f/4 lens from Panasonic. With a 2.3x crop factor, that lens works out to be 16.1mm-32mm, which is still respectively wide. However, if you go the route of adapting wide-angle, APS-C-optimized glass paired with a Speedbooster, you can go ever wider, or get a similarly wide angle of view at a much faster aperture.

Tokina 11-16mm f/2.8

When paired with the Speedbooster, a Tokina 11-16mm f/2.8 becomes an effective 7.8-11.4mm lens with a constant f/2 aperture. While not quite as wide as the native Panasonic 7-14mm, the extra two stops could definitely come in handy. The 35mm equivalent field of view of this lens when shooting 4K video on the GH4 would be approximately 18mm-26mm.

Sigma 8-16mm f/4.5-5.6

For those wanting to go as wide as possible on a rectangular lens, the Sigma 8-16mm will fill the bill. When paired with the Speedbooster, this lens becomes an effective 5.7-11.4mm, with approximately an f/3.2-4 aperture. The 35mm equivalent focal length, when shooting with a 2.3 crop factor for this lens, works out to 13.1mm-26mm, which should be wide enough to please any wide-angle enthusiast. This lens will almost certainly vignette slightly when used with the standard Micro Four Thirds 2x crop factor.

Samyang 10mm f/2.8

The new Samyang 10mm f/2.8 lens is a relatively fast manual focus prime lens optimized for APS-C cameras. It's resold under a few different brand names, including Rokinon and Samyang. Paired with the Speedbooster, this lens becomes an effective 7.1mm f/2 lens, a full 2 stops faster than the 7-14mm Panasonic, with just as wide of a field of view. The 35mm equivalent of this lens with the Speedbooster works out to approximately 16.3mm. While this lens is available with a Micro Four Thirds mount, using the Nikon mount version allows you an extra stop, and a wider angle of view, when you want it.

Fast 50mm

Another popular lens segment is the fast 50mm lens. Micro Four Thirds has a number of fast 50mm equivalent lenses, like the Voigtlander 25mm f/.95 and the Panasonic 25mm f/1.4. But going the route of a Speedbooster and adapted glass can give you similar results at a lower price. Here are a few APS-C prime lenses that could fill this gap.

Nikon 35mm f/1.8

The Nikon 35mm f/1.8 is a relatively affordable lens that's designed for its DX (APS-C) series DSLR cameras. Paired with a Speedbooster, it becomes approximately a 25mm f/1.2 lens that will give you around a 57mm (35mm equivalent field of view) when shooting 4K video with the GH4.

Sigma 30mm f/1.4

The Sigma 30mm f/1.4 is a little wider and a little faster than the Nikon 35mm 1.8. With the Speedbooster, this lens becomes an effective 21mm f/1.0 lens for Micro Four Thirds. The 35mm equivalent field of view is 49mm. This lens is a great option for those looking for the closest to a 50mm field of view when shooting with the 2.3x crop mode on the GH4, as even the native 25mm lenses will offer a field of view closer to 60mm.

Constant Aperture Zoom Lenses

When shooting video with a zoom lens, it's important to have a constant aperture to avoid the abrupt exposure changes that are common with variable aperture still lenses. Luckily, there are a number of high-performing APS-C constant aperture zoom lenses available from a number of manufacturers, for a lot less expense than the few constant aperture zoom lenses available for Micro Four Thirds.

Sigma 18-35mm f/1.8

The Sigma 18-35mm f/1.8 is a pretty groundbreaking lens for APS-C cameras. Offering an aperture typically reserved only for prime lenses on a constant aperture zoom, predictably, turned a few heads. When paired with the Speedbooster, this lens becomes an impressive 12.8-25mm f/1.2 effective lens, which is faster than most primes available for Micro Four Thirds, with the convenience of a zoom lens.

Tamron SP AF 17-50mm f/2.8

For those needing a little more zoom range than the Sigma 18-35mm offers, who aren't hampered by a mere f/2 effective aperture, the Tamron SP AF 17-50mm f/2.8 is a great option. Paired with the Speedbooster, it's like a using a 12-36mm f/2 on the GH4 when shooting 4K video. Its flexible range is great for handheld shooting.

Sigma 50-150mm f/2.8 OS

The Sigma 50-150mm f/2.8 is an APS-C replacement for full frame 70-200mm lenses. Paired with a Speedbooster, it becomes an effective 36-107mm f/2 constant aperture lens. This is a great medium-telephoto zoom lens option for the GH4. The current version of the lens also offers Optical Image Stabilization; however, since the Metabones Speedbooster does not provide power to the lens, users will not benefit from it. It might be worth looking for the older, non-OS version of this lens, which can be found for at a more affordable price in the used market.

These are just few of the many great lens options for the GH4, as the Micro Four Thirds lens mount is extremely adaptable. Hopefully, some of these suggestions will get you get started if you decide to use a Speedbooster.

  Effective Focal Length with Speedbooster 35mm Equivalent Focal Length with the 4K Crop & Speedbooster
Tokina 11-16mm f/2.8 7.8-11.4mm f/2  18mm-26mm 
Sigma 8-16mm f/4.5-5.6  5.7mm-11.4mm f/3.2-4 13.1mm-26mm 
Samyang 10mm f/2.8  7.1mm f/2  16.3mm 
Nikon 35mm f/1.8 25mm f/1.2  57mm
Sigma 30mm f/1.4  21mm f/1.0  49mm
Sigma 18-35mm f/1.8 12.8-25mm f/1.2  29-57mm 
Tamron SP AF 17-50mm f/2.8  12-36mm f/2  28mm-82mm 
Sigma 50-150mm f/2.8 OS  36-107mm f/2  82-245mm 

Discussion 95

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One big problem- the Metabones ruins the quality of your image.  It adds reflections, softens the image and throws your focus scales off on your lenses.  You are far better off NOT using a Metabones!

We're sorry your expereince with Metabones did not meet your expectations. The Nikon G to MFT Camera has a 5 Star rating with 26 additional customer comments to review.

"Wow, this thing in a wonder!"  "Sharpness and IQ are superb."  "This thing is amazing."

Sorry but that is nonsense. The Speed Booster actually enhances the image and brings out more detail and less contrast.

If Phillip said it I believe it! Thanks Philly Phill!!

I agree with Phil! My visuals have come out even better with the Speedbooster on my GH4. 

Yep I must say I cannot disagree more with ur comment. I have never experiencsd a soft picture or problem with focus scales, I found it actually improved the image 

I greatly enjoy the metabones speedbooster, but the way folks have been measuring it's effect on aperture seems off to me. On an m43 sensor w/o a speedboster, isn't f/1.4 effectively f/2.8 in terms of DOF(if you're using a 2x crop sensor), and thus, wouldn't the effect of the metabones has actually make that lens f/1.988? Or am I totally misunderstanding this whole thing?

It can be confusing, but basically f/stops are the focal length divided by entrance pupil diameter. Since the Metabones Speed Boaster reduces focal length by a factor of 0.7x but a lenses aperture opening remains the same, the effect f/stop becomes 0.7x smaller, or one stop faster.

Depth of Field (DOF) is a relation between the lenses focal length, the f/stop used, subject distance, subject size in camera (magnification) and camera to subject distance.  If you use a 50mm lens on a full frame camera and frame a head and shoulders picture, if the same lens is used on a MFT camera, the same image will put the camera further away from the subject effectively increasing DOF.

According to Metabones web site: “Note that a 35/1.0 lens (from 50/1.4 + Speed Booster®) will always have shallower depth-of-field than a straight 35/1.4 lens at any given distance.”

So would a 35/1.4 lens(from a 50/2 + speedbooster) have a DOF a) shallower b)same c) larger than a straight 35/1.4 lens at any given distance?One to think about!Yossi O please reply thanks.

If you have a straight 35mm f/1.4 lens or a 35mm f/1.4 equivalent from a 50mm f/2.0+Speedbooster mounted to cameras with the same size sensor, the Depth of Field answer is: B. Same.

Can you explain the calculations behind the Sigma 18-35mm f/1.8 being a 12.8-25mm equivalent? I wanted this lens, but I was calculating it out to be a 27.9-54.25mm lens on the GH4 + Speedbooster.

They meant the equivalent M43 lens would have that mm where you are talking about the equivalent full frame sensor setup

We added a chart showing all the lenses discussed focal lengths and adjusted focal lengths for the GH4's MFT sensor. I hope this makes more sense and I apologize for the confusion.   

the lens equvelent is correct, your 18-35 would efectivly become a 12.8-25mm Lens. however you do still need to take into account the 2X crop factor once you put said lens onto the actual camera, basically you take the lens 18-35 multiply that by 0.71 you will get the lens conversion. you then times that by 2 to equate to the 2 times crop factor you get with the M4/3 on the GH4 and that is what you have on your camera, effectivly once attached with a  speed booster this lens will act as a 25.56 - 50mm

For GH4 do You recommend Sigma 18-35mm F1.8 or Lumix G X 12-35 F2.8?

Intention is to do both set-up shoots and also to run and gun.
And is the Sigma lens compatible with the GH4 depth from focus system for fast autofocus?

Greetz and thanks for answers.

As you need an adapter to use the Sigma 18-35mm f/1.8 on the GH4, the lens would not retain auto functions such as autofocus.  If autofocus is a must for you, then the Lumix 12-35mm f/2.8 will be the way to go.  And, the Lumix 12-35mm f/2.8 is an excellent lens.  It would be a great option for a standard zoom to use for both run and gun and static shots.

does the new Metabones Speedbooster for Canon EF lens (since it's an active adapter) enable autofocus / autoexposure on Sigma 18-35mm lens (with canon mount)?

Autofocus would not be supported with the new Metabones EF to Micro Four Thirds Speed Booster.  It will allow for control of the camera’s aperture from the camera, though, so auto exposure modes should also be possible.  With third party zoom lenses, such as the Sigma 18-35mm f/1.8, the lens might need to be registered with the Speed Booster first in order to detect its maximum aperture.  You can find details on how to do this on the Metabones site.

This is interesting hint as canon FF glasses might be possibly combined with Sigma 18-35 which is an APS-C lens, hopefully this is without vigneting. Can anybody prove that this lens is fully compatible with EF to M43 metabones speed boster? Thanks a lot

This combination will work.  We have tried it out in-house with success, and there is not any vignetting. 

Why not use full frame nikon lenses with the speedbooster?

Like which ones?
The Sigma one has gotten mad reviews.
But at the same time since camera is Panasonic, then a panasonic lens has some good features like O.I.S

Well this blog talks about using DX lens designed for cropped sensors and I was wondering why not full frame glass

I reckon because its not a full frame camera.

Nor is it a APC frame camera.  The whole point of Metabones is to put on glass bigger than the sensor.  Otherwise it doesnt work.  You obviously don't understand but its not complicated.  Really looking for a response from the guy that wrote the blog as to why he didnt mention full frame glass.  

I think he focused on APS-C specific lenses because many of them are cheaper than full frame lenses - cost-effectiveness being something he highlights in this article. Also, there are some great super fast zoom lenses for DX, where-as you can't get something crazy fast like an 11-16mm 2.8 or 18-35mm 1.8 for full-frame. At least not that I'm aware of at anything near affordable. And since the speedbooster effectively makes it an APS-C sized sensor, why focus on more expensive and slower full frame glass? Obviously you could use those lenses if have some lying around...

The main reason I focused on APS-C lenses only in this article is that the lens circle of APS-C lenses paired with the Micro 4/3 Speedbooster is almost a perfect match for the reduced sensor area the GH4 uses when shooting 4K video, it's even closer then native Micro 4/3 lenses. Also Super 35mm film, the standard for cinema, is very close to the size of APS-C.

Since the Micro 4/3 Speedbooster won't reduce the image circle enough to use all of a full frame lens's image circle, using a full frame lens with the Speedbooster will be a lot like using a full frame lens on an APS-C camera (when shooting 4K video). Which leaves a bit of a hole when looking for extremely wide or wide and fast lenses. Using APS-C lenses allows almost their entire image circle to be used in 4K video mode, and actually a little more than the image circle they were designed for when shooting stills, which is why some may vignette in still mode. Designing lenses for smaller image circles allows for faster apertures, wider focal lengths, and smaller and lighter lenses compared to using lenses designed for larger sensors on cameras with smaller ones. 8mm on APS-C is just as wide as 12mm on full frame, but 12mm on APS-C is obviously not as wide as 8mm.

There are, of course, a large amount of excellent full frame lenses available that would work great with the GH4 and the Speedbooster, it just wasn't the focus of the article.

Thanks for your response Chris.  Just wanted to check compatibility as I'm very interested in getting the Samyang Cine lens kit for Nikon full frame as then I can use them with the speedbooster on gh4 to get s35 sensor size but also be able to use them on any full frame camera like the 5D or the new Sony A7 series.   It's a nice thought to have a set of cine lenses which will literally work on almost any camera I may or may not buy in the future.

 I don't suppose you know if there is any difference in optical quality between the normal MFT speedbooster and the one made for blackmagic cinema camera.  I'm aware of the mechanical shutter issue and the slight speed advantage. Just wondering if the edge sharpness is better or any other issues I'm not aware of.

kind regards


When used on the Blackmagic Cinema Camera its optical performance is similar to the standard version, however if you are talking about using the Blackmagic Cinema Camera speedbooster with the GH4 I wouldn't recommend it. Though I haven't tested it, I doubt the corner performance (on the GH4) will be very good since it isn't designed to project an image that large, metabones would have put little effort into making it work well. Metabones themselves state they are not for any other Micro 4/3 cameras.  Also (as you may be aware, though it's still worth reiterating), you can damage the GH4's sensor when mounting the BMCC version of the speedbooster depending on how the infinity focus is set, or if you accidently use the shutter it will damage both the camera and BMCC speedbooster since the shutter will actually hit the back of the BMCC speedbooster.

One thing to note on using FF lenses is that since you will be only using more of the center of the image, you will be getting more of the typical sweet spot of the lens, ie. Not the edge where resolution sometimes fall off.

These lenses include F-Mount lenses, does Speedbooster F mount nikon lenses?

The Metabones Speedbooster featured in the article is a lens adapter that would allow one to mount lenses with the Nikon F-mount onto a micro four thirds body.  All of the lenses in the chart above would require a lens adapter (such as the Metabones Speedbooster) in order to mount them on the GH4.

There is a rumour that Metabones are going to make a speedbooster especially for the GH4 making turning the 4k x2.3 crop to a S35 sensor size.  Which would mean in HD mode it would be even bigger!

Wonderful explaination lenses to use keeping the Sensor Crop factor in mind on the GH4 in the 4K Mode.

Thank you for this great article! One advantage of shooting video with DSLRs ist that one can also shoot stills...if I understood correctly the 4k video mode has a different crop factor than the still mode? if that is correct would the speed booster / sigma 18-35 f/1.8 combination have vignetting at still photography?


Yes, this is correct. During 4K capture, the GH4 can only use the center portion of it's sensor resulting in a crop factor of 2.3X vs 2.0X for still shooting.  When used in combination with the Metabones Speedbooster, the Sigma 18-35mm lens will be an equivalent 25.6 –50mm lens and in 4K 29.4-57.2mm. There is no vignetting when shooting still images.

For shooting 4k and UHD video, could I use a regular Nikon adapter (such as the Novoflex) on the GH4 with the Sigma 18mm - 35mm lens? I don't necessarily need the extra stop.

You don’t have to use the Metabones Speed Booster.  You could use a normal Nikon mount adapter, such as a Novoflex adapter, to mount a Nikon mount Sigma 18-35mm f/1.8 on the GH4.

I just bought the gh4 and was thinking about buying the speedbooster for canon FD lenses. The old lenses have a manual aperture ring so everything is still functionall and the canon FD lenses are cheap. But know I see Tamron SP AF 17-50mm f/2.8 in your list, does this mean I can use this lens whit the speedbooster and stil adjust the aperture? (on camera or lens/adapter) I will be using the gh4 just for film and do need to be able to adjust the aperture. I sure hope someone can help me with a clear answer, I'm just to new in this to figure it out and can't risk the money by just gambling and hoping it all will work out. Thanks in advance!

If you purchase the Nikon mount Tamron 17-50mm f/2.8, you could use the lens with the Nikon lens to Micro Four Thirds Speed Booster.  You would be able to control the aperture of the lens through a ring on the adapter.  There isn't a Canon EOS to Micro Four Thirds Speed Booster, so you do need the Nikon mount of the lens.

Thank you Chris for the article. You mentioned that there are some great full frame lenses to use with the gh4. Would you be able to provide some examples, thank you!

In the article Chris speaks of how it is more ideal from a photographic and cost benefit analysis to use the the Nikon F mount Metabones Speedbooster with APS-C/DX lenses, not full frame lenses, with this camera.  You can of course use, with an adapter, most any full frame lens you wish with no appreciable deleterious effect.

Sigma APO 70-200mm F2.8 EX DG OS HSM

Does this lens work with the Nikon fit metabones speedbooster on GH4? Or is it full frame?

You can use the Nikon mount Sigma APO 70-200mm F2.8 EX DG OS HSM with the Nikon to Micro Four Thirds Speed Booster on the GH4.  While this is a full frame lens, it can be used with smaller format sensors.

Thanks Kindly Christina. 

Could I ask please

1. How it works from full frame onto m43 ( throught the speed booster). Is there a circle gap or anything like that? (I cant wuite work out what happens - as new to this)

2. The f stop and focal range (again with booster)





You're Welcome JohnyG. As for your other questions:

A full frame lens will have an image circle that is large enough to cover a full frame sensor, so there is no issue using them with sensors that are smaller.  There is also no issue using a full frame lens with the Metabones Speed Booster, as it has a larger image circle than a DX or APS-C size format lens.

The focal length of a lens is the measurement in mm from the optical center of the lens to the focal plane.  This measurement is not dependent on which camera the lens is on.  So a 70-200mm lens will have a 70-200mm focal range regardless if it is on a full frame camera or micro four thirds camera.  What will change is the angle of view.  A lens shot on the GH4 (while recording 4K) with the Metabones speed booster will have an angle of view equal to roughly that of a lens with 1.63 X the focal length shot on a full frame camera.  That being said, the 70-200mm shot on the GH4 during 4K recording with the Speed Booster would have roughly the same angle of view as a 114.1-326mm f/2 lens.  Feel free to email us with further questions:


Correct me if I'm wrong, I'm just trying to figure out WHY people are crunching numbers.

If I'm not mistaken, the important part is the relationship between the body and the lens. If you have a M43 body and use a M43 lens, then you have full-frame right? 35mm = 35mm.

So the reason people will use the Metabones is to use non-Panasonic M43 lenses? or simply to adjust the crop-factor when shooting in 4k? Which results in a super complicated mathematical debate on what focal-length you are actually shooting.

Quiz: Jimmy has a GH4 Body(Micro Four-Thirds Sensor) and wants to shoot at 35mm focal length. Which lens does he get and does he use the Metabones when shooting at...




The GH4 has a MFT sensor. However, in order to avoid pixel binning and it's attendant moire and aliasing, the sensor is cropped to the precise size for 4K. This results in an approximate 2.3 crop from full frame.
By using the Metabones Nikon G & F Lens to Micro Four Thirds Mount Camera Speed Booster, you can reduce this cropping effect to an effective 1.42x crop. This is virtually the same as APS-C or Hollywood's Super35 imagers. Yes, that right, this is about the same size imager that has made thousands and thousands of Hollywood classics.

So if Jimmy wants to shoot with a 35mm focal length, he can just put on a 35mm lens. If he wants to shoot with a full frame 35mm focal length Field of View, then Jimmy can use a 20mm.

And one more thing. In a gift from the gods of Metabones, the Speedbooster makes your lenses brighter by one whole stop. This is incredible news for all who have struggled to shoot in low light before.

HI. I recently bought the tamron 17-50mm lens. Canon mount.  But I cannot adapt it to my Micro 4/3 GH3. Can anyone help, please? Is there an adapter I should be using? Or is it not possible to get an adapter with an aperature ring for canon? Should I have bough the nikon mount? 

please please please, help. 


You can mount Canon-mount lenses on a micro four thirds cameras.  As for aperture, with Canon-mount lenses you have two options.  When you want to change the aperture, you can take the lens off of an adapter, mount it on a Canon camera, then adjust the aperture to your desired f-stop, and then re-attach to the lens to the GH3.  Or, you can get an adapter that has a built-in Iris.  This will help control how much light reaches the sensor.  Unfortunately, though, there isn’t an adapter that will be able to control the aperture of the lens itself when using Canon-mount lenses on a micro four thirds body.  Otherwise, you would want to get the Nikon mount of the lens.  Click Here for lens adapters for the Canon mount.  Click Here for the Nikon version of the lens.