Review Atomos Shogun: 4K 4:2:2 in 10 bits

Panasonic and Samsung delivered unique cameras in 2014 with the Panasonic GH4 and the Samsung NX1. With these compact system cameras, you can make beautiful 4K/Ultra HD (3840 x 2160) video. You can even store the video recordings directly on an SD card. Many (semi-)professional videographers and film-makers were surprised by the image quality and the versatility of these cameras, as well as the beautiful background blur in comparison with traditional video cameras with a smaller sensor. With the Panasonic GH4, you can also store the shots with an even higher image quality… if you have an Atomos Shogun!

There are not yet any external 4K recorders on the market, aside from very expensive professional recorders. The Atomos Shogun is a first, with a calibrated, 7-inch, full-HD screen, including storage for high-quality 4K video recordings. For less than 2,000 euros (if you include the right HDMI cable, a link to secure the Shogun on the hot shoe and a small hard disk in the price), you are the man. Is it really true?
Atomos Shogun in practice: no childhood illnesses, but do look out for updates

Have Philips, Sony, Panasonic or Samsung ever sold a video recorder where you have to wait for a firmware update in order to review the recordings? Atomos has. And I don’t think it’s that bad. The Atomos Shogun is intended for video professionals and prosumers. This review is written for a photographer who is getting acquainted for the first time with all the great things that video and the Atomos Shogun have to offer. Anyone who is still unfamiliar with video will encounter a few new trade terms from the professional video world. In the article “Getting to know the Atomos Shogun,” I briefly laid out the functions of the Atomos Shogun and the concepts that appear here regularly (such as 4:2:2, 4:2:0 data compression or 8-/10-bit color depth). I advise experienced videographers to read the Atomos Shogun reviews in any case, which are included just above the conclusion to this article. The Atomos Shogun was brought to market very early. That is quite understandable, because videographers have been begging for it. Various essential functions will only become available with future firmware updates, for both Panasonic and Atomos. Thus, the user interface includes a large Play button, that doesn’t work. The functionality of being able to play back recordings made with the Shogun on the Shogun will become available later. I didn’t find it to be a problem, because I immediately took the hard disk from the Shogun home, placed it in the included docking station and assessed the recordings made on my PC. But if I had thought in the field that I had made a sensational recording, then I would have found it quite unfortunate that I couldn’t review it until I got home. You cannot (yet) operate the Panasonic GH4 with the Atomos Shogun, meaning that you have to use multiple screens in order to make video recordings. Hopefully, this will change quickly. The biggest surprise for me was that the device switches itself off without an express warning when the battery is empty. I did not realize what was going on. There is an indicator that shows the state of the battery, but I don’t pay attention to that (obviously) when I’m filming. I would have preferred a big warning that the battery was (almost) empty and that the Shogun would be shut off. A battery is empty in 20 minutes, but it takes a few hours before it’s fully charged again. The purchase of larger batteries with charger is a must for anyone who will be working with the Shogun for an extended period in the field. At home, you can use the included wall plug. The included case is of flawless quality. I had no concerns at all about transport damage. For anyone who has never before made video recordings with an external recorder, it takes some getting used to having a screen on top of your camera that happens to be larger than the camera itself. The Atomos Shogun is made of Gorilla glass with a plastic back. It feels solid, but it doesn’t seem to be built like a tank (the reputation that previous products from Atomos had). It probably saves weight, but when placing the Shogun in the hot shoe of the camera, I was always worried that it would accidentally fall. It would surprise me if the Shogun survived that without cracking. On the sides of the Shogun, there is a large number of external connections, including XLR plugs for an external microphone. My current microphone, with a simple jack plug, could not be connected. In order to cool the image processor, there are ventilation holes in the side, so that you have to be careful that no moisture enters the Shogun when it rains. And when the sun shines, the shiny monitor cannot be read. There is not yet a sun cap for the Shogun, but it’s coming. Buy one immediately when it’s available, I would say. If someone working with video for the first time already encountered points like those I’ve named here within a few days, then other reviewers will surely find a few more, perhaps more serious, points. Even so, this is not an experimental product with childhood illnesses. Insofar as I’ve been able to determine, everything works the way it’s supposed to. I had no software problems at all. The recording of a video with the help of a 7-inch screen with a resolution of 1920 x 1080 pixels is a pleasure. Focusing entirely manually is much easier when you enlarge the image 2x on a 7-inch screen. In no time, you will be spoiled by the image quality of the large screen and the simple-to-operate interface of the Shogun. And then you will be quite disappointed when you have to use the electronic viewfinder or the screen on the back of the camera. The adjustment of the white balance with the Vectorscope and checking the exposure with the Luma Overlay (see “Getting to know the Atomos Shogun” for an explanation) were new for me as a photographer. It may be an enormous leap forward from working with a histogram, and yet I miss the histogram. I had to get used to it, and at the same time, a whole new world opened up for me. I’m sure to come back to that in a future article.
Practical recordings 4:2:0 8-bit vs 4:2:2 8-bit vs 4:2:2 10-bit
Atomos Shogun offers Sony A7s owners the ultimate option for finally being able to film in 4K. Owners of a Panasonic GH4 or Sony A7s have, thanks to the Atomos Shogun, a view of 4K video recordings with more accurate brightness and colors because there is less data compression applied (4:2:2 instead of 4:2:0). In addition, the recordings from the Panasonic GH4 can be stored with more colors (10 bit instead of 8 bit) on the Atomos Shogun. The more bits, the more colors. The most common RGB files can describe 16.7 million colors (“8 bit”=256256256 = 2⁸2⁸2⁸ = 2²⁴) or more (“10 bit”= 102410241024 = 2³⁰ through 16 bit 2¹⁶2¹⁶2¹⁶=2⁴⁸). Two separate worlds? The maximum color depth of Photoshop is 32 bits; Premiere Pro goes to 10 bits. For photographers who are accustomed to carrying out editing in 16-bit TIFF or PSD files, it might be a surprise that videographers work with 8-bit files (comparable to jpg). Adobe Premiere Pro is for videographers what Adobe Photoshop is for photographers. Both programs are among the very best. Even so, I was dreading having to edit files in a 10-bit color space, when I am used to a 16-bit color space. Initially, I thought about saving video images from Premiere Pro as TIFF, and I was planning to then edit the images in Photoshop—because I am more familiar with that—in order to investigate the differences between 8-bit and 10-bit recordings. Premiere Pro, however, saves all TIFF files—even if you start with a 10-bit file—as 8 bits. So my options were limited. For more advanced color editing of video recordings, Adobe SpeedGrade and Adobe After Effects (with color editing in 32 bits) will be used.
Feat

Sensors of system cameras (both SLR and mirrorless) register colors in 12 or 14 bits. Photos will be stored in 8-bit jpg files, which with 16 million colors include sufficient color information for perfect prints. But photographers who do a lot of editing prefer RAW files with their higher color depth. RAW files, due to that high color depth, however, are much larger. It thus also takes more time to save RAW files than jpg files. An SLR camera makes a maximum of 10 images of 20 megapixels with a 14-bit color depth per second. And that can’t be sustained longer than 2 seconds. If you make a 50p Full-HD video, then you save 50 shots of 2 megapixels in the camera without interruption. A 4K Ultra HD recording consists of 8 megapixels, so the data stream there is much greater than with full HD. Camera designers face enormous challenges in holding the heat production with video recordings (and Liveview) within limits. That is the reason that some SLR cameras drop the mirror after a while during Liveview. With video (and as far as I’m concerned: also when working in Liveview), you naturally don’t want that. Without data compression and a lower color depth, it just isn’t possible to make a video recording in sufficiently high resolution and color depth. Panasonic, Samsung and Sony have accomplished a feat with the first system cameras with 4K video. And the Panasonic GH4 does even a bit more with the Atomos Shogun. That a Panasonic GH4 is able to deliver, uninterrupted, Ultra HD/4K images of 8 megapixels in 10-bit color depth and 4:2:2 data compression 25 times per second to the Atomos Shogun is currently unique for a camera under 2000 euros. Even the Sony A7s is not able to do that. These are specifications that belong to professional video cameras costing 10,000 euros or more.
Color reproduction
It must be said that the color reproduction of the Atomos Shogun screen can be calibrated. The colors of most external screens and screens on cameras never entirely correspond with the real colors. In the studio, you therefore make use of a screen that you calibrate regularly. In the field, you now also have with the Atomos Shogun a calibrated screen available. Very nice. If you use a photo or video without doing any editing (contrast, sharpening, levels, white balance and other color adjustments), then you’re fine with 8 bits. An 8-bit 4:2:0 shot that is stored on the SD card of the Panasonic GH4 is just as nice as a 10-bit 4:2:2 Apple Pro-Res HQ file.
But if you edit your shots, you pull the colors away from each other, and color transitions become blocky. Sometimes, colors become less natural, and the edited color photos start to resemble a watercolor painting. This is called posterization. Above, you see posterization in an extreme partial enlargement of an underexposed shot, where the exposure was significantly corrected afterwards. After editing, there are visible quality differences, but will these be caused with less data compression (4:2:2 instead of 4:2:0) or with more/more accurate colors (10 bit vs 8 bit)?
S-log: Strange guys, those videographers?
At the top right, you see (a part of) the adjustments that I have used for the video recordings of this swan. Move your mouse over the picture for the edited shot, which much better corresponds with what I saw.
Because videographers use 8-bit files, there is less space to repair overexposure or underexposure afterwards without visible loss of quality. Photographers who shoot in RAW worry about it less; they just correct exposure in Photoshop or Lightroom. In order to be certain that your video shots include as few overexposed or underexposed parts as possible, quality-conscious videographers use very different color profiles than photographers. Videographers work with Flat Picture profile, S-log or Canon log color profiles, which result in contrast, sharpness and sometimes saturation are lowered in comparison with color profiles that you use for photographs.	{youtube}3nmYksA7-Rg{/youtube}
If you compare an 8-bit video recording with a solid bicycle, then a 14-bit RAW file is a moped. With S-log and good color grading, videographers manage to keep up with the 14-bit moped on their 8-bit bicycle in terms of image quality. Without a special video color profile, the white feathers on the left next to the eye of the swan would have been fully bleached out—and the video recording would be hopelessly lost. The histogram of the end result shows a perfectly exposed recording, with great contrast and no under- or overexposed parts in the photo/video. There are color nuances that have been lost in the middle tones; you see that in the gaps that appear in the histogram as a result of color editing. Fortunately, the loss of color information was not so bad that I could discover any visible loss of quality. A very nice function of the Atomos Shogun is the application of a color correction profile on the screen. Video recordings that you make with an S-log or other image style have much less contrast than the original and the final result. That makes it, for example, more difficult to get an idea of how the final video will look. Focus peaking also becomes more difficult. A bit hidden in the menu is an option with which you can see a lively image on the monitor, while a soft image will be stored: that is perfect for color editing. It even appears to be possible to use an external CLUT (color look-up table) for this.
Posterization
In a histogram, the number of pixels with a specific color or brightness (vertical) will be displayed agains the color/brightness (horizontal). At the left in the histogram, you see the number of darker pixels (0) and all the way to the right, the number of intensely colored pixels (255). The histogram shown here, in which the intensity of the green light is shown, illustrates what happens when you make an 8-bit file lighter. Many of the darker colors have disappeared, recognizable by the gaps in the histogram. The more and the larger the gaps in the histogram, the greater the chance that the shot will look so unnatural that you will recognize in the image that it is heavily edited.
Click (2x) on this histogram for the histograms of two test shots with a greatly magnified image cutout, made with 8-bit 4:2:0 and 10-bit 4:2:2. If you greatly magnify the image, then you see that the 4:2:0 image is more blocky—in other words, has fewer color nuances—than the shot that is made in 4:2:2. This is called posterization.
Video: 4:2:0 vs 4:2:2
Videographers by an Atomos Shogun because they have high expectations of the quality improvement from applying less data compression (4:2:2 instead of 4:2:0). In his extensive Atomos Shogun review, Stefan Czech shows a great practical example of a lens with strong vignetting, where the quality difference between 4:2:2 and 4:2:0 is clearly visible. A large part of the quality improvement of 10-bit 4:2:2 files of the Atomos Shogun with respect to 8-bit 4:2:0 files out of the camera will thus possible result from 4:2:2. The question remains of whether there is a difference between 8-bit and 10-bit files that you can save on the Atomos Shogun. If there is no difference, you can choose the smaller 8-bit files without worrying about it, because it saves a lot of storage space.
Video: 8-bit vs 10-bit color depth
I do not expect that the 4:2:2 10-bit will be a killer feature of the Atomos Shogun. For practice shots where color corrections are only applied to a modest degree, I saw no difference in image quality between 10-bit and 8-bit Pro Res HQ files. Most probably, the vast majority of users will be satisfied with the smaller Pro Res 4:2:2 files. That saves a lot of disk space. But if more extreme color corrections will be applied, there are such differences. I made a few heavily (maybe 4 stops) underexposed video recordings with the Panasonic GH4, whereby the videos were stored in 8 bits and 10 bits by the Atomos Shogun in Pro-Res HQ. I exported one still from the 8-bit 4:2:2 video from Adobe After Effects as an 8-bit TIFF to Photoshop and converted it to a 16-bit TIFF. I also exported the same image, but from the 10-bit 4:2:2 video, from Adobe After Effects as a 16-bit TIFF to Photoshop. I then recovered the exposure and contrast of both files in Photoshop in precisely the same way. In the corrected shots, I could not discover any quality differences in the color reproduction of an 8-bit or 10-bit file. It can be seen in the histogram that the 10-bit recording withstood this extreme editing in Photoshop a bit better than the 8-bit version. In the coming months, I intend to find out whether the difference between 8 bits and 10 bits makes a difference in practice. Move your mouse over the picture below for a comparison of both files.

{insertgrid=117}	{insertgrid=118}
Conclusion Atomos Shogun review
Pros “Affordable” external 4K recorder Delivered in a solid case with many accessories Platform is designed to be able to work with future developments Beautiful image quality for the screen (calibration possible!) and for the recordings Useful features that you do not have on the camera, such as Luma overlay, false colors, or the use of a CLUT A pleasure to work with and a very user-friendly interface	Cons Camera cannot yet be operated from the screen Screen is not readable in bright light, and the sun cap is not yet available Life of a battery is very short (20 minutes) Charge time a battery pack is very long (2 hours) Playback of files is not yet possible
TL/DR (Too long, didn’t read?): This article is for real nerds who love high-quality video. The Atomos Shogun (Click here for the current price) is an external monitor including storage for 4K cameras, with which you can save even higher-quality images (4K in 4:2:2 10 bits!). If you have a Sony A7s, then I would order an Atomos Shogun immediately in order to be able to enjoy 4K. For Panasonic GH4 owners, that is more nuanced, but they can also get a lot of pleasure out of an Atomos Shogun. The Atomos does not yet (January 2015) offer all the functionality that the system can offer. For example, you cannot yet review recordings on the Atomos Shogun. You also cannot operate the Panasonic GH4 from the Atomos Shogun. Hopefully, that will change quickly with future firmware updates. Even so, we’re not dealing with a prototype that has childhood illnesses. Everything that the Atomos Shogun has to offer works perfectly. From the testing that I have done, it appears that the image quality of 10-bit files made with the Panasonic GH4 and stored with the Atomos Shogun is higher than that of 8-bit files, and that 4:2:2 is qualitatively better than 4:2:0. The good news is: the Panasonic GH4 delivers beautiful 4K Ultra HD recordings directly to the SD card in the camera, that become even more beautiful if you use full-HD videos. The bad news is that the tomfoolery that I had to engage in in order to show that the image quality of externally stored files is better will rarely be reflected in practice in video recordings. If you have the time and the money to go on an adventure with the Atomos Shogun, then you will be making video recordings in the image quality of the future. If you don’t want that, you can simply enjoy the 4K images that you store directly on the SD card in the camera.