Why do cameras lose focus on certain objects? Can current technology make it so that losing focus is no longer a thing?
In: Physics
When people say “camera”, they usually mean a device that uses some arrangement of lenses to focus the light from a scene onto a (normally) flat detector of some kind (film or a digital sensor) that records the focused light.
Some cameras have automatic focus, and there are several methods they might use to achieve this (often by analysing the light in the scene to look for clues about what part of the image needs to be in focus). There are several ways the camera can get this wrong. For instance, the variation of light in the scene might not be well suited to the method the camera uses, or the camera might struggle to lock its focus on a moving subject.
There are new devices, “light-field cameras” which are not yet very widely used yet. These do not work in the same way as what we normally think of as cameras; they do not record the light onto a flat (or curved) detector. They record light information in a completely different way, that allows the focus to be adjusted to the required part of the image _after_ the image had been recorded.
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