Aperture
Also known as: f-stop, f-number, iris
The opening inside a lens that lets light through, written as an f-number. It controls brightness and depth of field. Most action cameras have it fixed.
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What it means
The aperture is an adjustable hole in the lens. A wide aperture, such as f/1.8, lets in a lot of light and creates a shallow depth of field with a blurred background. A narrow aperture, such as f/11, lets in less light and keeps more of the scene sharp.
The f-number is a ratio, which is why smaller numbers mean bigger openings. Each full stop, such as f/2.8 to f/4, halves the light. Aperture is one of the three parts of Exposure, together with shutter speed and ISO.
Action cameras and most phones have a fixed aperture, so exposure is managed only with shutter speed and gain.
How it works in practice
Some drones with larger sensors offer an adjustable aperture, and pocket gimbal cameras and mirrorless cameras do too. On a drone, closing the aperture a little can help in bright light, though an ND filter is usually the better tool because it keeps the lens at its sharpest setting.
With a fixed aperture, the only ways to control brightness are shutter speed, ISO and filters. That is why ND filters matter so much for action cameras when you want natural motion blur in bright sun.
Lenses are usually sharpest a stop or two away from their widest setting, which is worth remembering on drones with adjustable apertures.
What to watch out for
Very narrow apertures, such as f/16 and beyond, soften the whole image through diffraction, especially on small sensors. Closing down to fight bright light can make drone footage look less sharp than a mid aperture with an ND filter.
Changing aperture during a shot, for example when auto exposure adjusts it, can shift depth of field and brightness visibly. Lock it for important shots.
Finally, a wide aperture on a large-sensor camera makes focus critical. If the subject moves, it can drift out of focus, which action cameras avoid with their deep, fixed focus.
How RawClip handles it
RawClip uses your footage as recorded and does not change focus or depth of field. Clips from drones, mirrorless cameras and action cameras can share one order, and the AI combines them into one highlight.