Flicker on camera: temporal or spatial, the right diagnosis

The wall looks perfect to the eye, but on camera it flickers, bands scroll through, or a wavy pattern appears. Two very different families of causes hide behind these symptoms — and much time is lost treating one while believing you are fixing the other.

Quick answerScrolling lines or bands on camera are a TEMPORAL problem: refresh rate too low, missing genlock or unsuitable shutter angle. A frozen wavy pattern that moves with framing is a SPATIAL problem: moiré, fixed by distance, focal length or focus — not by refresh.

Scan lines: the camera sees what the eye cannot

An LED wall lights by scanning. At 1,920 Hz refresh the eye sees nothing, but a fast shutter freezes the scan lines.

For everyday capture (TV sets, filmed conferences, livestreams), aim for at least 3,840 Hz refresh. For cinema, commercials or tight shots in virtual production, 7,680 Hz is the reference.

Refresh is set in the receiving card configuration (RCFG file on NovaStar, equivalents on Colorlight and Brompton), within the module driver IC's limits. Do it outside show time, with the configuration backed up first.

Genlock and shutter: synchronize everyone

Lock camera and video processor to the same reference signal (genlock) whenever the wall goes on air or into a recording.
Match the source frequency: a graphics card output at 59.94 Hz into a wall expecting 60.00 Hz produces a slow beat, visible as a brightness ripple.
Set the camera shutter angle to a multiple of the wall's period (180° at 1/50 s in 25p, for instance) and fine-tune on a monitor.
In virtual production, use the processor's dedicated functions (ShutterSync or equivalent) rather than stacking manual corrections.

Moiré: an optics problem, not an electronics one

Moiré is interference between the wall's pixel grid and the sensor's. No refresh setting will change it.

The effective levers: move the camera back (rule of thumb: minimum distance in metres ≈ pitch in millimetres), open up to reduce depth of field, shift focus slightly behind the wall, or change focal length.

If moiré persists on an imposed shot, a light diffusion filter in front of the lens remains the last resort.

When to call an engineer

Imminent shoot, refresh to change on a wall in operation, or beats resisting genlock: have the full chain validated (source, processor, cards, camera) before touching configurations.

A failure right now? Lédia, our AI engineer, guides you step by step, 24/7, photos included.

Talk to Lédia See pricing

Frequently asked questions

The wall also flickers to the naked eye — same problem?

No. Flicker visible to the eye points to a 59.94 Hz source into a 60 Hz wall, a scan incompatible with the configuration file, or a weakening power supply. Fix the source output frequency first.

What refresh should I ask for on a TV set?

3,840 Hz covers everyday broadcast capture. Tight shots, slow motion and cinema call for 7,680 Hz. Below 1,920 Hz the risk of visible lines is high.

Moiré disappears when I step back two metres — is that a real fix?

Yes. Moiré is geometric: past a certain pixel density per degree of field, the interference vanishes. Stepping back, zooming wider or slightly defocusing are perfectly legitimate production fixes.

Does raising the refresh have drawbacks?

Higher refresh slightly reduces maximum brightness and available grey levels depending on the driver. Hence aim for the value your use case needs, not the absolute maximum.