Sony's Senior Product Manager, Gary Mandle provides a thorough briefing on the BVM-X300 - in context with the technologies for which it was designed.
BVM-X300 OLED MASTER MONITOR
High dynamic range cameras have been around for a while, but until now, it’s been impossible to really view an image from a camera like the F5, F55 or F65 as it was originally captured. The best you could hope for was to archive the raw content and wait for the display technology to catch up. Now, there is a solution that allows direct viewing at full range without the need to make any conversion LUTs or changes to the native image. Sony’s BVM-X300 is a monitor that has been in design and development for more than 5 years. It made its official debut at the 2014 Hollywood Post Alliance (HPA) Technology Retreat at Indian Wells Calif. The BVM-X300 solves a majority of issues that previously required “work-arounds” when using the latest HDR cameras. Issues like black levels, wide color gamut, and 14 stop dynamic ranges all had to be compromised when using currently available technologies.
Many projects are now required to be shot in 4K, but there is still a lot of confusion on what the definition of 4K really is. Look at the DCI specification and also the SMPTE recommended practice for cinema, and you will see that the pixel matrix is 4096 x 2160 pixels at a 1.89:1 aspect ratio. Most “4K” monitors available now use consumer panels based on the Ultra HD (UHD) TV standard, not the cinema standard, so they use a 3840 x 2160 pixel matrix at a 1.77:1 aspect ratio. Why is this distinction important? Most movie projects are authored in scope or flat aspect ratios. Scope is defined by a pixel matrix of 4096 x 1714 pixels (2.39:1), while flat would be a 3996 x 2160 pixel matrix. The entire design of the cinema mapping system works so that you don’t need to scale the image if the panel is a 4096 x 2160 matrix. However, if the panel is a 3840 x 2160 matrix, both flat and scope images must be scaled as 11/12ths to fit the panel. This can hide image artifacts and create scaling artifacts in the picture. Both will affect the next stages of the production.
The BVM-X300 uses a true 1:89 4K panel so scaling is not needed to show any format UHDTV or Cinema 4K.
Advantages of using OLED display technology
While it’s had success in diverse professional applications, OLED is still a relatively new technology for master monitoring. It offers image performance beyond that of the long-time standard — CRT — and, even better, the same engineers who designed the BVM CRTs are the same ones that designed the BVM-X300. The OLED panel designed for this monitor is controlled by a proprietary system designed by Sony engineers called Trimaster, which is employed across Sony’s high-end monitor line. So you can understand the level of performance that this monitor is expected to deliver.
If the signal specifies a zero level, the Trimaster EL OLED technology allows for each pixel to be turned completely off, with no light emitted. There is none of the backlight leakage you would expect in an LCD monitor.
The blue line in the graph shows the black performance of a topgrade LCD. The yellow line is from a Sony BVM CRT monitor and red shows the black performance of a Trimaster EL OLED monitor. This doesn’t mean that the monitor is too black. Aside from this graph are controls in the monitor to set the EOTF (gamma) to what is defined by the imaging standard. The black you get is a calibrated result. If you need to elevate this, then there are handle provided in the monitor’s control that can do this. One simple and repeatable solution is to use the CRT emulation EOTF in the monitor presets. This elevates black to perform as shown in the yellow line.
LCD & CRT Gamut Performance
Trimaster EL Gamut Performance
While the BVM-X300’s panel can now display HDR images, it must also have a system in place to match input bit number to a precise light output, and do this over 26½ million red, green, and blue pixels. The BVM-X300 can accept 12‑bit video inputs and has the processing power to accurately range them for perfect gamma performance, either as a standard dynamic range or in high dynamic range. The contrast range is larger than any other available display technology and the signal process is optimized for EOTF accuracy.
Color Gamut Accuracy
Most competitive monitors will show the range of the color gamut measured using the full brightness of the display. The more energy that can be output, the better the gamut will test. But most production applications seldom require using the brightness part of the image when making color decisions.
Sequential contrast measured using full white and black fields. Intra Frame contrast measured using the IEC 62341 standard.
Above are diagrams based on CIE 1931 color space. The top set of triangles shows the size of the displayed color gamut at maximum brightness. The bottom shows the size of the color gamut displayed at low brightness levels. In many cases, with LCD, Plasma, and CRT technology, the lower luminance images will turn to monochrome in the very dark part of the image.
Pixel Switching SpeedThe Trimaster EL OLED panels can switch between a “full on” to “full off” state very quickly. In fact it can switch several hundredths of a second faster than LCD, eliminating image smear when areas of the picture move quickly. This speed is so fast that it can induce flicker if not properly managed. The BVM-X300 has settings to control this flicker and not cause temporal image changes. Below is a comparison between an LCD panel and the Sony Trimaster EL OLED panel. The OLED switch is far faster and much more uniform than these older technologies.
High Dynamic Range is new to the display world. It’s one thing to convert light to electrons, but it’s a whole new ballgame to convert electrons into light, especially if it has to be a particular light that must meet set standards. Until now, the monitor would be calibrated to 100 cd/m2 for reference brightness, while for television you may have highlights up to 109 cd/m2. Given that the camera is recording highlights as much as 100 times this level makes for some compromise. The Sony cameras output one of three versions of S-Log. When using the BVM-E250 OLED monitor for example, you needed to build a LUT to bring the range back to within 100 cd/ m2 or use one of the S-Log settings in the monitor which will either compress the image into this range or clip the image to retain a proper S-Log EOTF. The BVM-X300 panel design displays images far brighter than the previous models. Now the image can be displayed in the same range that the camera captured it, eliminating the need for these image modifiers. No more need to compress or guess just what you have captured. Settings for S-Log 2 and S-Log 3 let you see the image exactly as captured without the need for any manipulation.
Color GamutsMost monitors in the field today have settings for the ITU-R BT709 color gamut. This is the range of colors that the display can present. Some monitors are better than others at hitting the color primaries. This accuracy of this will have a direct effect on what you perceive. Inaccuracies in the color primaries can lead to color errors that are not in the content. Chasing these errors can cost the production needlessly.
The BVM-X300’s completely new panel design not only allows the monitor to display HDR content, it also expands the range of colors that can be displayed. This is the first 4K monitor to do this. The BVM-X300 has presets for ITU-R BT709 and R BT2020. It also has a preset for DCI P3. These primaries are more accurate than our previous BVM series and give an exact representation of the content.
New Chassis Design
New to the BVM-X300 is the layout and menu structure of the chassis, which is simplified from previous designs. The control panel has been integrated into the chassis. The slot structure of the older design is removed and emphasis is placed on the quality of the signal process, the accuracy of the image and the stability of the monitor. With a design this sophisticated, it wouldn’t be uncommon to go for months without needing to calibrate it. This new design has multiple stability feedback circuits that monitor the light output of the monitor. These maintain its accuracy over long periods of operation. This also provides the confidence that the monitor is right even though it may not have been checked in recent days. This also gives the production the confidence that the monitor used on the other side of the world looks the same as the one they have on set of in post. Everyone is always seeing the same image regardless of location or age of the monitor
The control panel has been simplified as well as the menu system. We’ve removed many of the settings that previously caused confusion in setup. A new menu tree lets you navigate through the monitor quickly and make configurations very simple. Configurations can be combined and stored, and can be assigned to one of the seven function keys on the control panel for instant recall. These configurations can be password protected so that they are always correct.
Power consumption is also significantly reduced when displaying an HDR image. So much so, that in a typical configuration displaying an 1000 cd/m2 HDR image, the power consumption is as low as 200 watts.
Time is at a premium during production. Sitting around a monitor trying to get the image right is tedious and costly. The first menu to display is a status window telling you everything from the monitor settings to the signal input format and even software versions and time in use.
Buttons under each manual control take the control out of preset so they can be adjusted. There is a light showing that this control is not in calibration. When setting these for the user configurations, they can be used to bring back the setting to a previous value in case they have been misadjusted.
Menu navigation is through one knob and two buttons. The knob allows selection and entry of a memory setting. A back button lets you step back one level and a menu button turns the menu on or off.
Congratulations to the team. Sony OLED TRIMASTER EL Series Professional Monitoring Technology Honored with Scientific and Technical Academy Award®
Left to Right: Ichiro Tsutsui, Mitsuru Asano, Masahiro Take [at podium], Mitsuyasu Tamura.
Photographer Michael Yada/© A.M.P.A.S.
Go to the 'What is HDR?' Feature Interview
Learn more about Sony’s HDR and OLED technologies
*It maybe hard to see the effects described, without an actual HDR display.
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