Light perception by the human eye, cameras, and measurement devices

Mantas shares his practical experience and explains how he finds balance between the human eye’s adaptive vision, the limitations of cameras, and the objectivity of measuring devices.
This part is not only about light — it’s about how we actually perceive it.

How would you explain the differences in light perception between TV cameras, light-measuring devices, and the human eye?

They are enormous! Yet our goal remains the same: the visual image of the show must look equally good to both the live audience and the cameras.

The human eye is an incredibly adaptive organ. It handles a dynamic range of about 20 stops, instantly adapts to different light levels, and “fills in” missing color information. When it comes to color tone and white balance, our visual system is extremely flexible — the brain automatically corrects color perception under varying conditions. That’s why we perceive a white shirt as white both in the shade and under tungsten light. Among all wavelengths of the visible spectrum, the eye is most sensitive to green.

The camera is not. It has a range of 7–10 stops, a fixed white balance, and lacks the adaptive flexibility of the eye. If the camera’s color temperature is not calibrated correctly, the image shifts — going green, bluish, or orange.

Measuring devices (spectrometers) are objective. Modern spectrometers use linear CMOS/CCD sensors with a sampling resolution of ~5 nm, covering roughly 80 data points across the 380–780 nm range. They reveal exactly where spectral gaps or “dirty” frequencies occur. Sometimes only the spectrometer can explain why two light sources that appear identical to the human eye look completely different on camera.
For example: on one show, the rig included fixtures with LED sources and others with HID lamps. The LD matched them visually using CMY color correction — to the eye they looked identical. But on camera, they looked totally different. The uncompromising spectrometer revealed why.

Where do you think the “truth” of light perception lies, and how does this knowledge help in your work?

The “truth” of light perception is a compromise between physical reality and subjective experience. It requires both technical understanding and trained perception.

In terms of contrast, visual arts for centuries have relied on the human ability to distinguish tonal values across the visible spectrum. Despite the eye’s wide dynamic range, masterpieces of painting often fit within just 5 stops (1:32 brightness ratio), and the eye perceives that as a complete tonal scale from black to white.

Excessive contrast in stage lighting does not always enhance emotional impact — it can overstrain the viewer’s visual system, reducing overall perception quality. It’s like staring at the sun at noon: the immediate brightness is quickly replaced by discomfort. In lighting design, the role of contrast is not to blind, but to support the scene’s dramaturgy and emotional depth.

The eye’s sensitivity to green also explains why low-CRI sources often look “unnatural,” with a greenish cast especially noticeable on skin.

So while I trust my eyes as the organ of perception, and instruments and cameras as measuring and capturing tools, the best results come from finding balance between natural human vision and technical limitations.

How do you deal with flicker and luminous output issues when working with different light sources?

Flicker: Not always possible to eliminate completely. Flicker usually occurs when a camera’s frame rate does not match the mains frequency of fixtures or LED walls. The first step is to synchronize all equipment to mains frequency. Adjusting camera shutter speed to 1/50 or 1/60 sec, or using Clear Scan (CLS) to fine-tune shutter speed, often helps. When not all fixtures can be adjusted, we prioritize the most important ones for the image — typically key/front light or LED screens.

Luminous output: This is about fixture power. Issues arise when adapting to existing ambient light conditions.

Example 1: Grand Palais in Paris — the challenge was to soften harsh daylight shadows or create color looks under strong natural light. That requires very high-output fixtures, because of the vast space and high rigging points. If power is insufficient, more fixtures must be added.

Example 2: filming a religious ceremony in a candlelit church — here the goal is to preserve the intimate atmosphere. Fixtures must dim smoothly, avoid flicker, and blend tonally with the warm, low-intensity candlelight.

Now we move to a key topic in modern lighting — technology development. What are today’s most relevant tools for theatre, broadcast, and hybrid shows? What can state-of-the-art fixtures do, and how are they transforming the work of lighting designers?

How do you see the future of theatre and broadcast lighting with new technologies and fixtures such as Ayrton?

The future is already here. These are LED-based fixtures, with passive or silent active cooling, high CRI (90+) or variable CRI, CMY color correction, flicker-free operation. Spot and beam types, with native color temperatures around 6500K. Simple in terms of setup and maintenance, but extremely versatile functionally. And importantly — camera-friendly, with the ability to adapt color rendering to the camera sensor.

And yes — everything is moving toward hybridity: light + video. We no longer separate the stage into “lighting” and “content” — it’s one living organism. Effective control of such systems requires high-speed networks using protocols like Art-Net and sACN, providing sufficient bandwidth over Ethernet. Traditional DMX512-A and RDM remain essential for conventional fixture control but serve more as auxiliary protocols in hybrid setups.

What advice would you give to young lighting engineers and designers to achieve the best results in lighting faces, skin, and set pieces?

Learn to see! Always collaborate closely with other departments. If the project involves broadcast cameras — make friends with the DoP.

Study painting, color theory, and the psychology of color. Fall in love with light.
And remember: good lighting is not only about technology. It’s about vision, taste, and the desire to convey to the audience what you see and feel.