A basic look at the mechanics How a camera works A basic look at the mechanics

Aperture Controls the amount of light focused on to the image sensor

Shutter Controls the length of time the image sensor is exposed to light Your camera may not have a mechanical shutter

How images are captured A brief look at CCD and CMOS

Film Replacement Instead of film capturing an image, digital cameras will have a CCD or CMOS chip This chip will ‘sit’ behind the lens, in the same way as camera film

Photodiodes Photodiodes convert light (photons) into electrons A CCD/CMOS chip is made of photodiodes connected together in strips Photodiode

Charge-Coupled Device Light is focused onto a CCD array within the camera This array is formed by multiple CCD strips

Colour The array is covered with a colour filter CCD strips are either Red, Green or Blue and can only receive that colour The colour electrons are changed into voltage and passed to separate ADC Chips

Photosites Photosites ‘sit’ above the photodiodes The photosites store the photons of the appropriate colour Life-like colour is ‘interpolated’ through algorithms run by the on-board computer

Analogue to Digital Converter One CCD strip in the array will pass the electron to the colour matched ADC chip, via an electron to voltage converter Each separate strip is connected horizontally to the next strip of the same colour, to pass the electron along

ADC Function The ADC converts the voltage created by the CCD array into digital data This data is used to create and record the image taken

Complimentary Metal Oxide Semiconductor (CMOS) CMOS works in the same way as CCD, but has an electron converter with the photodiode and the ADC converter on the same chip This lessens the number of chips needed in the camera, making it cheaper, but can lessen the effective light capture of the photodiode

Sensor sizes