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

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

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

5. How images are captured
A brief look at CCD and CMOS

6. 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

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

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

9. 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

10. 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

11. 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

12. 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

13. 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

14. Sensor sizes