They can be super tiny, light, and very thin. They're the new cameras being developed by Caltech that use OPAs (optical phased array).
"We've created a single thin layer of integrated silicon photonics that emulates the lens and sensor of a digital camera, reducing the thickness and cost of digital cameras. It can mimic a regular lens, but can switch from a fish-eye to a telephoto lens instantaneously -- with just a simple adjustment in the way the array receives light," according to the lead investigator.
The OPA is a grid of receptors. They each can be controlled to take in light from a particular direction. So, when they focus all their 64 receptors on a target that has 2 lights on in front, the 2 lights are perceived in the recorded image. The concept can be scaled up from there to higher resolution.