The Camera

Camera obscura- its like a dark chamber.
Electromagnetic spectrum- is the range of all possible frequencies of electromagnetic radiation.
Visible spectrum- is the portion of the electromagnetic spectrum that is visible, it can be detected by the human eye.
Photographs- is an image created by light falling on a light sensitive surface.

Aperture- it is a hole or an opening through which light travels.
Shutter- is a common term used to discuss exposure time.
Exposure- is controlled by shutter speed.
Depth of field- its the distance between the nearest and fastest objects in a scene that appear acceptably sharp in an image.
F- stop- its the value that indicates the size of the lens aperture used during the taking of a photograph.
Focal length- the focal  lenght of an optical system is a measure of how strongly the system converges or diverges light.