Light quality — source size and distance
Whether light is hard or soft depends not on output but on how big the source looks from the subject. At the edge of a shadow there is a soft band where only part of the source is blocked (the penumbra). The larger the source, the wider this band and the softer the shadow.
- 1Small source — The soft band is narrow, so the shadow edge is crisp.
- 2Large source — The soft band widens and the dark core of the shadow shrinks.
- Move it closer — The same softbox looks bigger the closer it is to the subject, so the light gets softer. The catch: small movements by the actor change the brightness a lot.
- Move it farther — The source looks smaller and shadows get harder, but brightness changes less as the actor moves toward or away from it.
- Make the surface bigger — Diffusion, or bouncing off a wall or board, enlarges the surface the light comes from. Because it spreads wider, less light reaches the subject.
- When hard light fits — When the story needs crisp shadows: midday sun, window-bar shadows, a tense scene.
Color temperature — three approaches
Film lights handle color in three main ways. None is simply better; it comes down to how often you change color on set and how much output you need.
| Type | What it does | Things to consider |
|---|---|---|
| Fixed daylight | Outputs a single daylight color temperature | At the same size, it tends to win on brightness and efficiency. For warm light, add CTO gel and lose some output |
| Bi-color | Mixes warm and cool LEDs to adjust color temperature | One fixture works indoors and out. At in-between settings that blend both colors, it tends to be dimmer than a fixed fixture of the same size |
| RGB-type (full color) | Mixes several LED colors to create both color temperature and hue | Effect colors and green-magenta correction without gels. White light quality varies by model, so check color rendering figures and test |
Mix different kinds of fixtures in one scene and the color can look subtly different even when the kelvin numbers match. That’s because each fixture leans toward green or magenta (tint) by a different amount. Before the shoot, aim them side by side at a white wall or gray card and compare on a monitor; you’ll have less to fix on the day.
How to read color rendering metrics
Color rendering is how naturally objects look under a light compared with a reference light. Higher numbers mean closer to the reference, and 90 or above is often recommended for video lights.
| Metric | What it measures | How to read it |
|---|---|---|
| CRI (Ra) | How closely standard color samples look under the light compared with a reference light, as seen by the human eye | The most widely used, but deep red (R9) isn’t part of the average. If skin and lip tones matter, check R9 separately |
| TLCI | How little colors shift when recorded by a camera | Designed around camera capture, so it’s a useful reference on set |
| SSI | How closely the light’s spectrum matches a reference (tungsten or daylight) | A comparison metric that depends less on any particular camera. Useful when mixing different fixtures |
Flicker and shutter speed
Flicker happens when a light’s brightness pulses faster than the eye can see and falls out of step with the camera shutter, showing up as flashing or horizontal bands in the image.
- Mains frequency — Mains power runs at 50Hz or 60Hz depending on the country. Under lights that pulse with the mains, such as fluorescents and some indoor fixtures, a shutter speed matched to that cycle (1/50 or 1/100 on 50Hz, 1/60 or 1/120 on 60Hz) reduces flicker.
- LED dimming — Some lights flicker when dimmed very low. Check the dimming mode or frequency setting in the light’s menu.
- High-speed shooting — Higher frame rates mean faster shutters, which make flicker more visible. Test slow-motion shots at the exact settings first.
- Screens and signs in frame — Adjust the shutter speed in small steps until the bands disappear.
What to check before you choose
- Quality — hard or soft, and how much shadow you want to keep
- Color — whether a fixed color temperature is enough or you need to change color on set
- Color rendering — the metrics and R9, and color differences between fixtures you’ll mix
- Power — mains or battery, and power draw
- Flicker — a test shot at your frame rate and shutter
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