Irregular, wavy, organic flare pattern reminiscent of light refracting through water, produced by complex multiple reflections between curved lens surfaces.
Caustic Flare describes flare patterns that are not geometrically clean—no rings, no polygons, but rather wavy, almost liquid light textures, like the web of light threads at the bottom of a swimming pool. The name comes from optics: caustics are the focal surfaces on which refracted or reflected light rays converge. When multiple reflections pass through strongly curved or aspheric lens surfaces, precisely such convergences occur in the image.
Character Instead of Flaw
In test reports and flare libraries, the Caustic Flare is considered a characteristic feature, not a defect. It primarily occurs with optics that have unusual designs—vintage zooms, modified projection optics, series with hand-ground elements. Two copies of the same series can exhibit different caustics; this makes the effect difficult to reproduce but unmistakable.
Usage on Set
The effect requires a hard light source close to the camera and thrives on movement: even small changes in the angle of incidence make the structure flow. This can organically enhance an image—or make it restless if the texture moves across a face. Those who use caustics deliberately will block camera movement so that the structure remains in calm image areas.
Practical Tips
- Caustics are copy-dependent—document the specific copy during lens testing, not just the series.
- Slightly stopping down changes the structure more than with classic ghosts—half a stop can make the difference between texture and blur.
- Announce early in VFX shots: a real caustic in the plate is more complex to composite than a clean ghost.
Related terms
Quiz
1. Was beschreibt „Kaustik-Flare" am besten?
2. Zu welchem Department gehört „Kaustik-Flare"?