Ratio Switch

Background

Visible frame borders change to reveal or hide areas without stretching subject geometry.

Narrative function

Ratio Switch shapes how audiences read space, time, power, or emotion. Used with intention, it becomes part of the film's visual grammar rather than decoration.

How it works

Execute Ratio Switch with clear marks: lock lens, distance, lighting, and timing so the technique supports the beat. Rehearse once, then protect continuity across coverage.

When to use

• When the scene's emotion or geography benefits from Ratio Switch.
• When you want a readable visual motif that can pay off later.
• When a contrasting setup will make the next cut or reveal land harder.

FAQ

What is Ratio Switch?

A cinematic technique: Ratio Switch — a deliberate visual choice with readable grammar on screen.

When should I use Ratio Switch?

When the scene's emotion or geography benefits from Ratio Switch.

What is a common mistake with Ratio Switch?

Using Ratio Switch as a flex without story motivation.

Prompt

Includes camera move matched to the title, plus lens triad extras: focal length, aperture/T-stop, ISO, shutter, white balance, and the story being filmed.

16:9 cinematic demo: Ratio Switch.
Technique: The visible frame boundary changes to reveal or hide image area while subject geometry remains unstretched.
Scene: A station porter waits alone beside one luggage cart. A wider visible frame later reveals two receding pairs of matching carts near the platform's image edges.
Start: Initial 4:3 active window centered within a black 16:9 canvas; porter centered, only the nearest cart visible.
Motion: Keep the underlying camera locked. From seconds two to six slide the left and right side mattes outward symmetrically to reveal the full 16:9 plate; porter size and position stay fixed.
End: The full 16:9 window reveals the previously hidden edge profiles of four more carts in two receding pairs, while the porter and central cart retain exactly the same image size.
Camera: 35 mm rectilinear prime; fixed focal length, f/8, shutter 1/48s, ISO 400, 24fps.
Light: Use 5600 K daylight with a broad sky fill. The brightest direction comes from upper camera left; let ground bounce remain weaker and less saturated. Preserve white fabric and reflected water detail by controlling the exposure before adding the final grade. Meter the scene and select neutral-density filtration as needed to hold the stated aperture, exposure time and ISO; lock the filter during the take instead of using automatic exposure.
Color: Grey platform, dull blue carts and restrained orange coat. Preserve distinct shadow, midtone and highlight values within this palette; keep the named material treatment consistent between frames, with controlled highlights rather than a generic filter.
Duration: 8s. Mode: composite.

Related techniques

• Lens Flare

  Stray light inside the imaging optics creates source-dependent ghosts or veiling glare that changes when the source is blocked.

• Double Exposure

  Two image records coexist within the same frame through a controlled blend, instead of trading places as a transition.

• Split Screen

  Two separately photographed or generated image fields are visible at the same time within one composed frame.