When you use your camera to automatically choose aperture and shutter speed, what your camera is actually doing is using the built in light meter and measuring how much light is being reflected to the camera. photography came about to make drawing easier.Wave-Particle Duality of Light. Quantum theory tells us that both light and matter consists of tiny particles which have wavelike properties associaed with them. Light is composed of particles called photons, and matter is composed of particles called electrons, protons, neutrons.