How to Fix Crushed Blacks on Sony a7S and a7S II External Recordings

To say that the Sony a7 series of mirrorless cameras has been popular among videographers is an understatement. A large number of filmmakers have been using these cameras and some them make good use of the external recording feature to get even higher resolutions and data rates. 

Unfortunately, there has been a pitfall plaguing the cameras for a while now. Of course, I’m talking about the crushed blacks and highlights on external recordings. This article will take a deeper look at why this phenomenon appears and how to resolve it. Or at least, how to work around it. [UPDATE: We have developed a LUT that fixes it.]

crushed blacks sony a7s external recording

Crushed Blacks on External Recordings

It is no wonder that external recording is so popular on the Sony a7S. With the assistance of an external disk recorder, such as the Atomos Shogun, the possible resolution increases from 1080p to 4K and filmmakers can tap into high-quality codecs such as ProRes or DNxHD (as opposed to Sony’s H.264 derivative, XAVC).

Sadly, when using S-log2 Gamma Space, crushed blacks and skimmed highlights can make a surprise appearance at the editing desk. A good portion of the lows appear cut off, and some highlight information tends to be lost, too. In S-log3 only the blacks are affected (as the video output only goes as high as 94%). The contrast is raised and, in essence, the whole purpose of S-log is defeated. This leads to images that were perfectly fine during shooting becoming broken.

This phenomenon has been the main reason that some people have avoided using external recorders with the Sony a7S, a7S II, and a7R II cameras.

a7s internal vs external crushed blacks

What causes the Crushed Blacks Phenomena?

Let’s face it. We’re often quick to blame manufacturers when things like this crop up. In this case, however, it turns out the culprit isn’t Sony. After digging deeper into the matter, we discovered that the reason we lose image information on external recordings is that the NLE is incorrectly interpreting the data it is given—it doesn’t realise that we’re using the higher bandwidth Gamma (S-log2/S-log3). In our case, the NLE in question is Adobe Premier Pro CC 2015.

incorrect display range cuts off information leading to crushed blacks

Wrong display range settings of the video data cut off image information.

The image above is a waveform representation (captured in S-log2 with DaVinci Resolve) of a recording of an OEFC chart. In the camera’s S-log2 & S-log3 Gamma Setting, apparently data from 0 to 1023 is used for each channel. However, when no further metadata is embedded in the recordings, all NLE’s, including DaVinci Resolve, automatically interpret the footage recorded on external recorders with video levels from 64 to 960. This cuts off some information in both the blacks and the highlights. The orange arrows point out where that happens.

When you record in-camera (XAVC, for example), then metadata is written directly to the file to tell your NLE to use 0 – 1023 (If you’re working in 10bit). On external recordings, however, this metadata cannot be transferred via the HDMI cable thus either the recorder would have to set that metadata flag (which it probably doesn’t), or it has to be set in your NLE manually.

The Fix

[UPDATE:] We have developed a custom LUT that fixes this problem either in post, or directly on a recorder, so you have 0 rendering time and 0 quality loss. Get the LUT by clicking the button below, or read all about it here.


The Workaround

Unfortunately in the NLE’s that many of us use (Adobe Premiere Pro CC 2015 & Final Cut Pro X) there isn’t an option to manually set the data levels. The NLE will always automatically interpret the footage with levels from 64 to 960 (or 16-240 in 8bit) and this will cut information, leading to crushed blacks and skimmed highlights and there is no way to change that yet.

To correctly interpret externally recorded footage you will either have to switch to another NLE that lets you set this manually, or go through DaVinci Resolve, which allows you to re-interpret the footage. Fortunately, DaVinci Resolve is a free download.

[UPDATE]: Thanks to xdcam-user we realized there is a workaround directly in Premiere.

levelsAdobe Premiere Pro CC

To get your video levels back to include the full range of your external Slog recordings do the following in Adobe Premiere Pro CC.

After importing your footage to the timeline:

  1. Apply the effect “Fast Color Corrector” to your footage.
  2. In the effects tab on the “Fast Color Corrector” effect change your “Output Black” to 16 and your “Output White” to 235.

Make sure that the “Fast Color Corrector” is always the first effect in your filter-stack (before Lumetri for example), otherwise you will get the wrong results.

Your footage now uses the full range right within Premiere. Other “Levels” filters will not get your levels back by the way.

davinci-clip-attributesDaVinci Resolve

If you’re using an externally recorded clip from an a7 series camera, then go to the EDIT tab in DaVinci Resolve and right-click on the clip(s) you are importing in your library window. On the drop-down select “clip attributes.”


A window will open that lets you choose either “Auto”, “Data Levels” or “Video Levels”. By default this is set to “Auto”, but we want to select “Data Levels 0 – 1023” to properly display our S-log2 / S-log3 footage.

After all of your clips are set to “Data Levels”, drag them to the timeline where you will then be able to color the clips to your liking—with all information in the blacks and highlights. Once this is done, go to the DELIVER tab in DaVinci Resolve to export the clips.

Note that the above tip only applies to external recordings! When handling internally recorded files (XAVC) the levels should always be left to “auto”.

ae1Adobe Premiere After Effects CC

[Update: Here’s the fix for After Effects]
In After Effects the fix is a bit more tricky. First you have to open “Project Settings…” which can be accessed by right-clicking the small menu box on the project tab.

ae2In the window that opens you have to change your project’s Color Settings.

Click the “Depth” dropdown and select “32 bits per channel (float)”. Then click “Ok”.

ae3Now you have to apply the “Levels” effect to your footage. It can be found under Effects –> Color Correction –> Levels.

In the Effect Controls tab under “Levels” you can now set your ouput levels. Set Output Black to “0,0627” and Output White to “0,9255”. Those are the values that correspond to 16-235 in the 32-bit space.

Now your footage includes all data levels of Slog.

Besides being a more complicated workaround the real downside of this method is that it will considerably slow down your rendering speed.

Final Cut Pro X

Unfortunately Final Cut Pro X seems to handle the video range incorrectly as well and I have not found a fix. Although the xdcam-user article claims that Final Cut X handles superwhites correctly, this was not the case in my tests. To prepare externally recorded Slog footage for a correct grade in Final Cut X you will probably have to go through DaVinci first, or simply switch to Premiere Pro, like I did a while ago. I know many people out there love Final Cut X, so no offence please.

Future Solutions?

Of course, it would be an easy fix if Adobe and Apple would just give us an option to use the full range of levels in Premiere / After Effects & Final Cut Pro — just like in DaVinci Resolve. Apparently some users have been aware of this issue for a while, but so far there has been no direct implementation of such feature. We can only hope that this article will add some pressure.

If you are affected by this, you can help and let the software companies know by leaving a comment underneath and fill out the feature request form.

For Adobe Premiere Pro CC:  Adobe feature request form.
For Adobe After Effects CC:  Adobe feature request form.
For Apple Final Cut X: Apple feature request form.

[UPDATE:] We have developed a custom LUT that fixes this problem either in post, or directly on a recorder, so you have 0 rendering time and 0 quality loss. Get the LUT by clicking the button below, or read all about it here.


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Adrian Outlaw Reply
Adrian Outlaw March 28, 2016

question on the a6300 when u record in 4k and a monitor is attached the Face Registration turns off. is there a fix for this ?

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

I’m not aware of a fix for that. I think Sony will have to fix that via firmware.

Markus Lubenica Reply
Markus Lubenica March 28, 2016

Firstly fix your crushed 4k brainwash and don’t do the manufacturers parrot pinocchio style in your SEO/SEM affiliate marketing blogs. There’s no 4k on any Alpha series camera out there. Not internal, not external. It’s goddamn UHD, so go and figure! :P

Johnnie Behiri March 28, 2016

Markus Lubenica. Move on. A bit tiring listening to your 4K/UHD mantra.

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

Dear Markus,
I guess when you comment you hope for an answer, so here it is:
The term “4K” only appears once in my article, but it seems to have upset you quite a bit. Let me assure you we are not a SEO marketing blog, and a single iteration of the term “4K” would make little sense for a SEO/SEM blog.
But put that aside, regarding your anger about the UHD term, let me try to put things into perspective: DCI 4K has 6% more pixels than 4K UHD. The correct term of UHD by the way is “4K UHD” and UHD is actually just the short version. UHD could also refer to 8K UHD by the way. Add to that the correct way to say what you probably mean by “4K” is actually “DCI 4K”. And then there is 4K 4:3 also. Add to that, these formats actually describe aspect ratios, not resolutions. “4K” is what connects these formats and describes the high resolution size that comes after “HD”. So by referring to 4K, we refer to a resolution size, not a specific format like UHD, DCI, or even UWD, which are all 4K formats.
Since most television sets and computer screens are still 16:9, most cameras are optimized for 4K UHD. I think that makes total sense. Don’t you?
I hope it’s more clear now. Will answer more comments, but would appreciate a more respectful tone.
Happy easter!

Balder Akermo Reply
Balder Akermo March 28, 2016

Just wanna say; that was a wonderful reply for a trolling comment. Greatly appreciate all your work here. Thanks!

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

Thanks Balder. Good to see people appreciate our efforts, it’s not always easy… Best wishes for easter to you.

 Emile Modesitt Reply
Emile Modesitt March 28, 2016

Markus got destroyed!!! Haha. Somebody’s got a serious stick up their butt. And it seems ridiculous that Adobe hasn’t implemented a fix for this problem. With the millions of updates they roll out, you’d think they’d be able to add this feature which has a massive effect on workflow for so many filmmakers.

Markus Lubenica Reply
Markus Lubenica March 28, 2016

So, and why you’re hunting for „likes“ on a SEO brute force (self)marketing CMS platform like this, which serves a facebook ranking $ystem? C’mon, nobody runs a blog 24/7/365 for free ;) Coming back to the key facts…..sorry you’re simply technically incorrect. The term “4k” originally derives from the Digital Cinema Initiatives (DCI), a consortium of motion picture studios that standardized a spec for the production and digital projection of 4k content. In this case, 4k is 4096×2160, and is exactly four times the previous standard for digital editing and projection (2k, or 2048×1080. 4k refers to the fact that the horizontal pixel count (4096) is roughly four thousand. The 4k standard is not just a resolution, either… it also defines how 4k content is encoded. A DCI 4k stream is compressed using jpeg2000, can have a bitrate of up to 250Mbps, and employs 12bit 4:4:4 color depth. Ultra High Definition, or UHD for short, is the next step up from what’s called full HD, the official name for the display resolution of 1920×1080. UHD quadruples that resolution to 3840×2160. It’s not the same as the 4K resolution made above – and yet almost every TV or monitor you see advertised as 4k is actually UHD. Sure, there are some panels out there that are 4096×2160, which adds up to an aspect ratio of 1.9:1. But the vast majority are 3840×2160, for a 1.78:1 aspect ratio. And the same counts for the affiliate marketing hyped term „4k” on all Alpha series cameras. Now, it’s not as if TV manufacturers aren’t aware of the differences between 4k and UHD. But presumably for marketing reasons, they seem to be sticking with 4k in the consumer market which is overall wrong. So as to not conflict with the DCIs actual 4k standard, some TV makers seem to be using the phrase “4k UHD,” though some are just using „4k“ wich is again – wrong. To make matters more confusing, UHD is actually split in two – there’s 3840×2160, and then there’s a big step up, to 7680×4320, which is also called UHD. It’s reasonable to refer to these two UHD variants as 4k UHD and 8k UHD – but, to be more precise, the 8k UHD spec should probably be renamed QUHD (Quad Ultra HD). The real solution would have been to abandon the 4k moniker entirely and instead use the designation 2160p. Display and broadcast resolutions have always referred to resolution in terms of horizontal lines, with the letters “i” and “p” referring to interlacing, which skips every other line, and progressive scan, which doesn’t: 576i (PAL), 480i (NTSC), 576p (DVD), 720p, 1080i, 1080p, and so on. Now that there are 4K TVs everywhere, it would take a concerted effort from at least one big TV manufacturer to right the ship and abandon use of 4K in favor of UHD and 2160p. In all honesty, though, it’s too late. That said, 4k has already been bastardized, before it’s even really “out” per se. Consumers don’t have a clue there are industry specs for it. The only reason anyone has heard of H.264 is because Apple introduced the nomenclature to consumers via Quicktime. 4k is already just a marketing term and hyped by blogs for UHD content which is simply wrong. But we don’t need to exercise a fundamental debate about things that should be be widely clear. Anyway, Sony charges money from not very well enlighted consumers for features of a camera that doesn’t exist. VW gets sued for their exhaust value scandal world wide because they claimed some features that doesn’t exist. The main problem isn’t just the fact of manufacturers lies. It’s also about their affiliate marketing, their $hareholders do the 1:1 pinocchio parrot spec style. The customers are misled since years and learn technically and total wrong issues and finally agree to terms that aren’t true. That’s brainwash! Sony is aware of that and would never do that in their (Semi-) Professional lineup cause they would be eaten alive and loos a lot of $$$$$ clients. It’s just because most consumers don’t know the difference and they grew up and were teached by the profit bound industry to accept UHD as 4k. See Sony Bravia TVs, see all consumer line Alpha cameras, see their action sports cameras, see their mobile phones……. – but face that not Sony alone does that. Bottom line, selling UHD as 4k is a lie and technically wrong – so better correct this and your backlog.

Gentry Jonathan March 28, 2016

wooohooo!!! awesome post man. ‘lot of good stuff there.

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

Hi Markus, Good to get your perspective on this. I call for your source please, my sources differ a bit. It seems to me that you are mostly upset about the general consensus to call any format that has a resolution of around 4000 pixels “4K”, regardless of any standardisation that might have happened in the past. Really it seems most manufacturers of cameras, televisions and projectors (television and cinema), but even most users I see are ok to refer to these resolutions as “4K”. Personally I also think it makes sense to call it all 4K and I’m afraid I think you won’t be able to convince the whole world to use other terms. I think it’s a bit far fetched to say “it’s all a lie”. I know there are debates on what are the correct terms, but it’s too complicated for the end user, so we shouldn’t bother them too much with this stuff. I’d recommend to simply take it easy on this topic. 4K certainly isn’t a selling argument against UHD in my opinion. There are endless attributes about a camera that are so much more important. Nobody around here, and certainly I don’t want to mislead or lie, but rather do the exact opposite, so I’m not your enemy. But I’ll stick to the term “4K” like most people in cinema / video world seem to have agreed to do. Regarding our magazine’s running costs: Yes we have advertisements on the site by select manufacturers and links to our sponsors, but we recommend only the products we work with ourselves and we do not recommend many of the ones we test as you will no doubt see when you read our site. Also we work with retailers that sell all the products and we recommend those retailers as we use them ourselves, in order to make sure we retain our objectivity with our content. This is very important to us. So when you call us “a marketing blog” it’s actually “a lie” as you would call it.

Kotlos Kotlos Reply
Kotlos Kotlos March 28, 2016

Thanks for this report. When using slog2 with a7rii recorded internaly in premiere i can see the levels are between 16-235. I even see clipping at these levels so I was always under the impression that slog2 is using the reduced 16-235 range vs Cine4 that uses the full range.
In this article you claim that it is using the full range also in slog2 mode, am I correct?

Kotlos Kotlos Reply
Kotlos Kotlos March 28, 2016

Ok upon further inspection, Slog2 with A7r2 is using 0-255 range that premiere correctly identifies. The problem was that premiere incorrectly identifies Cine4 as being 16-235 and thus there is clipping.

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

Oh, really? I think Slog2 is 0-255. I just found a possible fix with a Plugin within Premiere. We will have to do further testing.

Kotlos Kotlos Reply
Kotlos Kotlos March 28, 2016

Yeah Slog2 is indeed 0-255, I was confused because Premiere correctly identified the 0-255 range of Slog2 but not Cine4. I though it default to 16-235 for all the profiles but I was wrong.

Jonathan Gentry March 28, 2016

This raises many questions in my mind. For example is this also an issue for other cameras like the GH4 with V-Log? Is this an issue when using the other 4K recorders?

Thanks for the heads up…

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

I don’t know about the GH4. I think it depends on how V-log works exactly. This is an issue with all other 4K recorders as well.

Gentry Jonathan March 28, 2016

Thanks for response. The GH4 has a setting in camera for 0-255 or 16-235 etc. I can’t remember if this is active when using V-log.

Would you say the issue is actually that there is no communication between the codec and the editor as to if the camera is using 16-235 or 16-255?

If that is the case you may want to reframe some of your article in such a way as to say that this is an issue for all cameras that use such a setup.

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

No, what I’m saying is that it’s definitely an issue for Slog2 / Slog 3. I did not research other log curves. Also there is communication between the camera and the NLE. BUT there is no communication when there is HDMI cable in between cause the metadata can’t be transferred. Actually I described this in the article but maybe it wasn’t clear.

Gentry Jonathan March 28, 2016

Hmmm… It just seems like the issue you are describing would have a larger impact than just the Sony A7S. Also in your instructions about the Adobe Premiere fix by xdcam-user it seems you are addressing only 8 bit numbers. You may want to specify if we can also use 10 bit range?

Sebastian Wöber Reply
Sebastian Wöber March 29, 2016

The a7 line mirrorless cameras only do 8-bit. I haven’t tested this in 10-bit on Premiere but DaVinci was setup in 10-bit, so it definitely works in DaVinci like described.

Sebastian Wöber Reply
Sebastian Wöber March 28, 2016

I update the article with a very easy fix for Adobe Premiere. I have not found a solution for Final Cut yet. If anyone finds one please let us know and I’ll update the article.

Tim Naylor Naylor March 28, 2016

Great article. Thanks.

Steffen Hacker Reply
Steffen Hacker March 28, 2016

Absolutely great article! Did not read anywhere else abot this, but everyone should know, that´s a big thing!! Thanks a lot!!
Recorded tons of A7s-footage on a Shogun and with the Fast color Corrector fix can now “Improve” the dynamic range of the clips – cool! Would love to have the same fix for After Effects, now one has to render out the whole thing via Premiere and import .. not ideal but better than no fix! :)

Sebastian Wöber Reply
Sebastian Wöber March 29, 2016

Hi Steffen. Challenge accepted…
I pulled a late night shift and figured this one out for you. Happy to report I just updated the article with the fix for After Effects as well. Unfortunately there’s a huge downside: Rendering speed. Maybe someone else will find a way to avoid the 32-bit color space. For now the method above will be your best bet in AE. Cheers!

Steffen Hacker Reply
Steffen Hacker March 29, 2016

You´re the MAN! ;) Tried the same quickly yesterday night as well, but was only in 16bit color space. But makes total sense .. renderspeed shouldn´t be a problem for most of us, just the fact that some plugins/effects don´t work or behave strangely in 32bit, but there´s always workarounds. Thanks!

 KC Bassett Reply
KC Bassett March 29, 2016

I’ve heard if you record in dnxhd instead of prores you wont come across this issue.

Yura Makarov Reply
Yura Makarov March 30, 2016

It would be great if companies such Atomos, Convergent Design and Video Devices would add this type of metadata to the video file. It’s seems like they can fix this problem on their end. I know there probably no way to determinate the type of signal you’re getting from the camera, but to have at least a manual switcher for extended shadows and highlights would be great.

Doug Sanford Reply
Doug Sanford March 30, 2016

Has anyone figured out a way to incorporate an accurate version of this fix into a LUT? It would be great to be able to automatically include it via Media Encoder’s built in LUT option, so that if you’re downconverting or doing any other sort of transcode as a first step the correct levels get baked into the new ProRes file. I’ve done a quick rough test with Lumetri vs. Fast Color Corrector and am not yet at a really viable solution – the Lumetri version looks very close when tweaked but the scopes show a much dirtier RGB parade vs. the Fast Color Corrector option, and I haven’t found a way in Resolve to export the clip settings as a LUT, as it’s not happening in a corrector node but in the media pool. Any thoughts would be really helpful!

Sebastian Wöber Reply
Sebastian Wöber July 4, 2016

Hey Doug,
I finally figured it out, though the hard part was to make it 100% accurate. Here’s the LUT:

Daniel McMahon March 31, 2016

Interesting article!
My question: Does this also affect 8bit Canon C-Log footage recorded to a 10bit Atomos recorder or is it linked to the higher 10bit output from the camera?

Thank you, Daniel

Sebastian Wöber Reply
Sebastian Wöber March 31, 2016

In theory this only affects Slog 2 & Slog 3 and has nothing to do with 10bit.
There is a certain probability the C-log is also using a wider range, but it has not been tested by us. Maybe someone else could confirm.

 Aung Lwin Reply
Aung Lwin March 31, 2016

I’ve just read this article and now I’m wondering if the internal recorded footage of the FS7 needs to be corrected in post as well. In Cine Ei mode I cannot change anything for the Whites and Blacks in the Paint menu and on the waveform display on the viewfinder the Blacks is hovering a bit above the bottom with the lens cap covered.

Sebastian Wöber Reply
Sebastian Wöber April 1, 2016

Again. It is not affecting internal recordings.

Jorg Ehrler April 1, 2016

Do you think this phenomena is in FS7+Atomos combo as well as your article states that the issue is in Slog2/slog3?

 Javi Montero Reply
Javi Montero April 10, 2016

Cine1 and Cine4 gammas at least on Sony FS5 goes upto 1023, so I suppose this trick is valid for those gammas. Correct?

 Dov Adler Reply
Dov Adler May 3, 2016

Hey Seb! Mitch from Convergent Design noted this issue and said that this phenomenon has been accounted for in the Odyssey 7Q+ firmware (see DVXuser thread here I haven’t personally tested whether this fix actually works, but if it does, perhaps other manufacturers of external recorders could implement a similar fix?

Sebastian Wöber Reply
Sebastian Wöber May 6, 2016

Thanks David. Haven’t had any success with the Legalize option yet. I’ve contacted Mitch and will update you on the status. So far it seems to me like it’s not fixing the issue.

Stephen de Vere June 18, 2016

Has anyone discovered a reliable source of info on what luma range is used in XAVC-S series Sony cameras – in particular the A7S and A6300?

I have a Sony EX3 that records super whites and a Lumix GH2 that records in 16-235.