Definition
What is aperture in video?
Aperture is the adjustable opening inside a lens through which light passes to the camera sensor. It is expressed in f-stops; lower f-numbers represent a wider opening and higher f-numbers a smaller one.
Opening the aperture admits more light and generally makes depth of field shallower, while closing it admits less light and increases the range that appears acceptably sharp. The visible result also depends on focal length, sensor size, camera distance, and background distance.
In video, aperture is a storytelling control as well as an exposure control. A wide setting can separate a face from its background; a narrow setting can preserve detail across a landscape. Because shutter speed is usually constrained by frame rate and motion blur, crews often use ND filters to keep their preferred aperture in bright conditions.
Example in the edit
On a sunny exterior, the cinematographer adds an ND filter so the lens can remain at f/2.8 for a soft background without forcing a very fast shutter speed.
Why editors use it
Aperture connects exposure with focus and visual emphasis, making it one of the most consequential controls in a camera setup.
Quick answers
Frequently asked questions about Aperture
Why does a smaller f-number mean a wider aperture?
The f-number is a ratio of focal length to opening diameter, so a lower value represents a larger opening relative to the lens.
Does aperture alone determine background blur?
No. Focal length, sensor size, focus distance, and the distance from subject to background also affect the amount and appearance of blur.
Should video aperture change during a shot?
Usually not unless the change is intentional, because a visible exposure shift can distract. Crews often control changing light with ND filters or lighting instead.