Bokeh
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Bokeh in bokeh cinematography is the aesthetic character of out-of-focus rendering: the disc shape, edge, and smoothness of blurred points, not the mere fact of a thin depth of field. The glass, not a blur slider, decides whether those discs are round, oval, outlined, or swirling.
Narrative function
A city, a string of practicals, or a wet street becomes a field of discs. Circular blades make circles.
Anamorphic squeeze makes ovals. Mechanical vignetting cats-eyes the discs at the frame edge.
Nervous, outlined, or onion-ring discs are also bokeh. They are just unkind bokeh.
Use it when the world behind or in front of a face should become light rather than information. One plane stays true.
The rest is the optic's handwriting. It is the wrong tool when you need the room.
If background signs, eyelines, or geography still have to read, creamy discs are hiding the scene. It is also the wrong word for a masked cutout with no optical discs at all.
How it works
Open the aperture, separate subject from background, and choose glass: spherical circles, anamorphic ovals, Petzval swirl, cat-eye at the edges. Point sources (practicals, speculars, rain catches) make the discs visible.
Distance and focal length set disc size. Prompt the disc shape and the source of the highlights, not blurry background alone.
When to use it
A close portrait in a cramped apartment, amber lamps and a magenta neon turning into circular or oval discs while the near eye stays sharp. Do not melt a wide master that still has blocking to read.
Compared with similar shots
Shallow Focus is the thin sharp plane. Bokeh is the look of whatever is off that plane.
Anamorphic turns those discs into ovals and often adds streaks. Rack Focus moves the sharp plane during the shot.
Bokeh can change as focus moves, but the pull is a different verb.
In film
In the Mood for Love turns crowded Hong Kong lamps into soft discs around faces. Her isolates Theodore against city lights whose character is the glass, not a painted smear.
Prompt it
Name disc shape and highlight sources. Example: Creamy bokeh field behind [Subject], circular or oval highlight discs from practicals, subject sharp, background as light not as a masked blur.
What usually goes wrong
Wrong cousin: a cutout mask or generic shallow focus with no disc structure. Tell: hair cut out like a sticker, no specular discs, background replaced rather than optically soft.
Fix: keep optical discs, cat-eye at edges if wide open, and a real distance between planes.
Questions
What is bokeh in film?
The character of out-of-focus rendering: circles, ovals, cat-eyes, swirl, onion rings. It describes how blur looks, not merely that something is soft.
Bokeh vs shallow focus
Shallow focus is a narrow depth of field. Bokeh is the optical handwriting of that blur. You can have shallow focus with ugly bokeh.
When should I use bokeh?
When only one plane may be true and the rest should become light. Do not use it when the background still has to carry information.
How do I prompt bokeh for AI image or video?
Specify circular or oval discs, name the highlight sources, keep the subject sharp, and forbid cutout edges or a smeared backdrop.
Melies can generate this Bokeh
Melies is the AI filmmaking workspace. This Bokeh opens with the optical prompt loaded, so the effect has a physical cause in the frame.