The Camera

aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane.

diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture.


image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras, camera modules and other imaging devices.

Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed.

focal length of an optical system is a measure of how strongly the system converges or diverges light.

f-number (sometimes called focal ratio, f-ratio, f-stop, or relative aperture^[1]) of an optical system is the ratio of the lens's focal length to the diameter of the entrance pupil