Dolly zoom (vertigo effect) prompt for Gemini Omni, tested cheap

To get a dolly zoom from Gemini Omni, name both halves of the move in the prompt: the camera moves toward the subject while the lens zooms out, so the subject stays the same size and the background stretches. Test it at 360p for $0.30 per 8-second take on Sume, and only pay for 720p ($1.00) or 1080p ($1.50) once the stretch is visible.

Camera-effect prompts are hit and miss. Budget three drafts.

Say what each part does

'Dolly zoom' alone can be read as a plain push-in. Spelling out the two motions and the visible result gives the model the whole effect. Google's Omni page advises plain-language description of the shot (read 2026-10-07).

• Motion one: 'the camera dollies slowly toward the man's face'.
• Motion two: 'while the lens zooms out, so his face stays the same size'.
• Result: 'the hallway behind him stretches and seems to move away'.
• Mood: 'cold fluorescent light, tense, silent'.
• Sound: 'low drone and a faint electrical hum. No dialogue.'

Draft request

Eight seconds is enough for the effect to build. Use 360p and a locked subject.

import os, requests

prompt = ('Vertigo dolly zoom, single continuous shot. A man stands still in a long '
          'office hallway. The camera dollies slowly toward his face while the lens '
          'zooms out, so his face stays the same size and the hallway behind him '
          'stretches away. Cold fluorescent light. Audio: low drone, faint electrical '
          'hum. No dialogue.')
r = requests.post(
    'https://api.sume.com/v1/videos',
    headers={'Authorization': 'Bearer ' + os.environ['SUME_API_KEY'],
             'Idempotency-Key': 'dolly-zoom-draft-1'},
    json={'model': 'gemini-omni-flash-1.1', 'prompt': prompt, 'duration': 8,
          'resolution': '360p', 'aspect_ratio': '16:9'},
    timeout=60)
print(r.status_code, r.json())

Draft, then finish

Sume bills list times 1.25 per second, rounded up to the cent per job, from the Video Router doc's list rates of $0.03, $0.10, $0.15 and $0.30 per second.

How to check the effect

Pull stills at 1, 4 and 7 seconds with the video frames endpoint and compare the size of the face with the width of the hallway. If the face grows, you got a push-in; if nothing stretches, you got a zoom. In either case, try the opposite word order, or reduce the scene to one fixed subject on a plain background, where the stretch is easier to see. Faces are the usual failure; a chair or a lamp at the same distance is a good test object before you commit to a person.

Other options for the effect

If the model will not produce the stretch, fake it from a clean plate: generate a locked-off clip of the subject, then make the zoom in a video editor. That route gives you control over the exact speed but needs a sharp, high-resolution source, and an Omni 720p clip has limited room for a crop. Sume's video filter and timeline tools are for processing and joining clips; they are not a replacement for a camera move inside the shot, so use them for edits around the effect, not for the effect itself.