What a camera is and how it works?

The most simple answer would be this: a camera is a light tight box with a lens attached or no lens at all (pinhole camera) and a light recording media in it (film, digital sensor).

OK, that's to simple isn't it? Let's go a bit deeper. The most important parts of any camera are: the light tight box - the film/sensor chamber, lens, shutter and aperture. SLR cameras have a mirror and a pentaprism.

Now, let's talk about each of them. Film/sensor chamber is a black, light tight box to ensure that no stray light gets inside it so the photographer can control the amount of light getting inside. The shutter is a device to control the light entering the film/sensor chamber. Aperture is another way to control the amount of light entering the camera. And the lens is a device to do all kinds of tricks with light by bending the light waves.

So, now we'll put it all together. Let's say we're taking a picture of a flower. The light coming from the sun reflects off the flower and travels into our lens, there, with the help of optical elements it is adjusted, then it travels through aperture, which is an adjustable hole (we'll take a closer look at it in the next post), then it is up against the shutter - the main door, the shutter is opened by a photographer for a certain time (now exposure is in progress), the film/sensor now records the image of the flower. The shutter closes, the job is done, you have the picture.
OK, these are the basics of any camera, in next posts we'll go through more complicated processes in picture taking technology.