LED walls are the cornerstone of ICVFX virtual production, but choosing the right one for your organization can be daunting. You don't need the most expensive wall, but your creative needs help define your technical needs.
CoPilot Co. has helped design and build custom LED volumes for Fortune 500 companies and production studios worldwide, and our clients often ask us what specifications they should look for. This guide breaks down the main LED wall specs to give you a good starting point.
Pixel Pitch
Pixel pitch is the distance between the centre of one pixel on an LED panel to another, measured in millimetres. The smaller the pixel pitch, the closer the pixels are to each other.
Pixel pitch is all about perception. If you're viewing something from far away, you don't need a super small pixel pitch. Take for example LED billboards — the space between each pixel is about 26mm, but the billboard still looks fine because it's meant to be viewed with the naked eye from far away.
LED volumes for virtual production, on the other hand, require a lower pixel pitch since cameras and talent will typically be filming from 8-15 metres away. Your needs will vary depending on your equipment and your distance from the wall, but a popular choice for virtual production is 2.3 - 2.6mm. Going lower will start getting expensive with some returns on quality, but may be necessary if you plan to be filming in a smaller space.
Resolution
Resolution refers to the visual dimensions of a display, measured in pixels (e.g., 1920x1080). A standard LED panel/cabinet made up of 4 tiles, with each LED being one pixel.
The number of LEDs or pixels on your panel is determined by the pixel pitch. With the standard cabinet size of 500 mm x 500 mm, the closer your pixels are to each other, the more there will be on your panel. A lower pixel pitch means a higher resolution. The resolution you should aim for depends on your project, the total size of your LED volume, and the space you'll be filming in.
Brightness
Brightness in LED terms is measured in nits. The standard for wall LEDs is 1500 nits, while ceiling tile nits tend to be brighter since they help light up a scene.
Unless you're shooting very bright scenes, most scenes will only require your wall to be at 300 - 700 nits. However, we strongly advise against panels that only go up to 800 nits. If you're going to be investing in an LED wall, you don't want to be restricted by its capabilities.
Refresh Rate
Refresh rate refers to how many times the image on your wall is updated per second, measured in Hertz (Hz). A higher refresh rate is ideal, since it produces less flicker and allows you to shoot at a higher frames per second (FPS).
The standard for virtual production is 7640 Hz, which will allow you to shoot at 60 FPS. Shooting on a wall with a lower refresh rate will limit the FPS you can shoot at. Not all projects will need to be shot at 60 FPS, but as we've emphasized before, you never want to be limited by your LED wall.
Scan Rate
Scan rate refers to the number of diodes that refresh on a tile in a row, represented as a fraction. For example, a 1/28 scan rate means that every 28 diodes refresh together. The higher your scan rate, the more scan lines will be visible when filming.
An illustrated example of
A better scan rate for virtual production is 1/8, though some companies are coming out with LEDs with a 1/1 scan rate. Lower is generally better, but most productions don't need a 1/1 rate. Factors like how big your wall is will determine what scan rate you'll need.
Viewing Angle
Most LED walls these days have 170-180° viewing angles, which means you won't be restricted to filming at exclusively one angle. The greater the viewing angle, the more flexibility you'll afford your team. Shooting on LED is already difficult; eliminating as limitations as possible will ensure your team has the freedom to produce the best content possible.
Colour Accuracy
Colour-accurate LEDs can make or break your shot. Each LED is made up of red, green, and blue (RGB) diodes, meaning there are no "true" whites. Instead, LEDs produce white light by lighting up all three diodes.
More expensive RBG tiles tend to be better at faking a "true" white. Opting for lower cost RGB LEDs can mean sacrificing colour-accuracy, resulting in hours of colour-correction in the editing room. Many cheaper LEDs produce a more pink or orange skin tone, making it difficult to achieve a natural look.
On the higher end of the price spectrum are RGBW tiles, which include a white diode to assist in producing a truer, more natural white. A great mid-range option is to use RBG tiles compatible with Brompton Technology Limited's TrueLight® processor, which uses X-ray emitters to expand the range of colours on RGB. This allows RGB tiles to emulate a "true" white similar to RGBW, but at a lower cost.
As a general rule, regardless of whether you choose RGB or RGBW diodes, you should order all your LED tiles from the same batch to prevent any colour inconsistencies. If you were to order 100 LED tiles today, then order another 100 tiles a year from now, there's a very real possibility that the colours will look slightly different on the new LEDs.
There are some plugins that can help calibrate them, but you can save your team the pain of that by just ordering all your LED tiles at the same time. If you need to order from different batches, you can place the tiles you already have somewhere where they aren't visible or aren't beside the ones you'll primarily be using. Use them as a ceiling tile, floating wall, etc.
Cabinet Design & Mounting
Cabinet design isn't the most important thing, but it can certainly help make your team's lives a lot easier. For example, certain cabinet designs allow you to pop out a single tile rather than having to unscrew and take apart multiple components, making it easy to replace an individual tile when a diode dies.
Square cabinets tend to be easiest to work with, but regardless of what shape you choose, you should opt for an LED tile that has a serviceable design.
Pointing a camera at LEDs is tough enough. Choosing a wall with the right specs for you helps make sure you never get caught in a situation where the LED is obvious and you need to fix it in post-production. The whole point of virtual production is to capture everything in camera so you don't have to edit it later. Take for example season 1 of The Mandalorian — their production team didn't use the proper specifications, so a lot of things had to be fixed in post-production.
Choosing the LED tiles that work best for you depends on the size of your space, the projects you plan to use it for, what camera(s) you'll be using, and more. If you need help figuring out the right specifications for your studio or organization, shoot us a message here: consulting@copilotco.io
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