Human memory is limited to several million facts and pictures are a great way to preserve or refresh memory. A picture may be a simple sketch or photograph taken from a camera. The last hundred years have seen cameras evolve from simple optical devices to fancy devices incorporating cutting edge technology. A novelty in the twentieth century, cameras are nearly considered essential in the modern world.
A camera basically captures light emerging from an object onto any kind of photo-detector that records the image which can be later copied on paper or projected on a screen. Popular photo-detectors are film rolls and photo-strips that are used in digital cameras. The specification of a camera is given by the size of its lens that captures light such as 35mm, 16mm, etc and 16mm film cameras are used by filmmakers to make movies of all kinds.