Broadcasting a sporting event in 4K/UHD gives fans a richer viewing experience with crisper images, a wide color gamut and greater image depth, but specific lighting thresholds must be met in order for the 4K UHD_ cameras to perform correctly in the space. This is often misinterpreted to mean that 4K UHD broadcasts must be recorded under much higher levels of light, which increases the energy used and wasted during every sporting event.
With the LED lighting technology available today, stadiums can support 4K UHD broadcasts and operate with greater energy efficiency, trimming lighting costs tremendously. The secret is selecting stadium lighting that provides the quality of light required by those 4K UHD cameras.
Light quality necessary for 4K UHD broadcasting
Light quality refers to the spectrum of light, or wavelengths of energy, produced by the light source. The complete visible light spectrum ranges from 380 nanometers to 780 nanometers and includes all colors of light, from red to violet. However, 4K UHD digital cameras do not use every wavelength of light in the visible spectrum. Instead, they use specific ranges of blue wavelengths, green wavelengths and red wavelengths present in the available light to recreate the myriad of colors in the 4K UHD images they produce.
If the light sources in the stadium do not produce enough blue light, green light or red light to meet the camera’s needs at a certain setting, the camera will open its aperture in order to allow more light to reach the camera’s sensor. Unfortunately, this adjustment compromises the depth of field view that is such an impressive part of 4K UHD broadcasts. To support 4K UHD broadcasting in a stadium, the lights need to provide the necessary levels of red, green and blue light, allowing the camera to keep its aperture in the optimal position while it records.
Light sources in stadiums today
Different light sources produce different blends of wavelengths in the visible light spectrum, dramatically impacting the ability of 4K UHD cameras to film in their environment. Consider the three most popular light sources found in stadium settings today: metal-halide, typical LED and optimized LED.
1. Metal-halide: Metal-halide fixtures produce light that does not contain much of the blue wavelengths and none of the red wavelengths needed by the 4K UHD cameras. While there is no way to add red wavelengths, stadiums will compensate for the low amount of blue light emitted by metal-halide fixtures by significantly increasing the light levels. The idea is that blasting more light onto the field will increase the quantity of blue wavelengths available to the camera. Unfortunately, this results in larger energy bills and a significant amount of energy waste since that level of light is unnecessary for the game being played on the field. Ultimately, despite higher light levels, with no red light emitted from the metal-halide fixtures, 4K UHD cameras cannot record events in these settings.
2. Typical LED: Most typical LED lights emit an incredible amount of blue light. After all, all LEDs are, in fact, blue. Different phosphors are applied to the diode to allow it to emit different wavelengths of light. While advancements in phosphor coatings have enabled typical LED lights to emit blue and green wavelengths of light, red wavelengths are still underrepresented, especially for 4K UHD broadcasting. Stadiums will attempt to compensate by increasing the light levels on the field. In some instances, stadiums have doubled lighting levels, jumping from around 200 foot-candles on the field to over 400 foot-candles, simply to provide the 4K UHD cameras with enough light. Even with twice the available light, the 4K UHD camera may need to open its aperture slightly to access a sufficient amount of red light.
Unfortunately, this approach creates a few undesirable effects. It is expensive and inefficient to provide so much light for a sporting event, and if the camera adjusts its aperture size, the decreases in the depth of field have a negative impact on the overall quality of the event recording.
3. Optimized LED: Some stadium fixtures feature LEDs that have been engineered to emit light rich in the red, blue and green wavelengths needed by 4K UHD cameras. These lights provide 4K UHD cameras with the light levels they need, without increasing the intensity of the lights beyond what is necessary for the game to be played on the field. In addition, the aperture of the camera can remain in its optimal position for recording events in 4K, providing the depth of field that creates such an impressive viewing experience. These optimized LED stadium lights enable stadiums to support 4K UHD broadcasts, while maintaining highly efficient performance.
It turns out that 4K UHD cameras don’t need incredibly high levels of light to record sporting events in ultra-high definition. They need high-quality light.