A dolly zoom, also called a zolly or Vertigo effect, is a camera technique that combines a physical dolly movement with a simultaneous zoom in the opposite direction - dollying toward the subject while zooming out, or dollying away while zooming in - so that the subject remains the same apparent size in the frame while the background dramatically expands or contracts. The result is one of the most psychologically disorienting effects in cinematography.

The effect works because dollying and zooming affect perspective in opposite ways. Moving the camera physically toward a subject draws the background closer as the camera advances, while simultaneously zooming out widens the field of view and pushes the background back optically. When calibrated correctly, these opposing effects cancel out their influence on the subject's apparent size while dramatically exaggerating the spatial distortion of everything around them. Alfred Hitchcock used the technique in Vertigo to convey his protagonist's acrophobic dissociation, and it has since become a standard tool for conveying psychological disturbance, sudden revelation, dread, or a character's shifting perception of reality.

When prompting AI video generation for a dolly zoom or zolly effect, describing the combined camera behaviors and the intended psychological feeling communicates the desired result. Phrases like "dolly zoom effect," "Vertigo effect with background expanding," or "camera advances while background rushes away" convey the technique clearly. As AI video generation capabilities for precise camera control continue to develop, more accurate recreation of this technically demanding effect becomes increasingly achievable through prompting alone.