How a Digital Camera Works
Learning the basics of how a digital camera works and knowing the functions of the key parts of the
camera can be very beneficial. It will help you make key decisions concerning proper exposures when you
are taking pictures. It can also help you decide which camera features are most important to you when
making a camera or lens purchase.
Digital cameras generally fit into two categories. They are Digital Single Lens Reflex cameras, also
referred to as DSLR or Digital SLR cameras, and there are Digital Compact cameras, which are often
referred to as Point and Shoot cameras. Although there are differences in the quality of the pictures, as
well as differences in the sizes and shapes of the cameras, they basically produce pictures or images the
same way. Check the tutorial Types of Digital Cameras for more details on the differences between these
type cameras. Ok, lets get to it.
A camera is basically a light proof box. When you press the shutter release
button, light beams are allowed into the camera through the lens. The light
entering the lens is directed to the camera's sensors. The amount of light
that reaches the sensors is determined by size of the aperture opening that
is set. The amount of time the light is exposed to the sensor is determined
by which shutter speed is being used. The color and characteristics of the
light that is exposed to the sensors is recorded and reproduced as the
picture or image. That is a super simple explanation. Lets take a quick look
at some of the parts of the camera and their functions.
The main parts of a camera are the body (the light proof container), the lens, the shutter, the aperture,
and the sensor.
The Camera Lens: The purpose of the camera lens is to focus and direct the incoming light. The lens
consists of one or more precisely shaped pieces of glass or plastic called elements. The light coming
through the elements is "bent" or directed to the sensor where the image is recorded. The camera lens is
an extremely important part of the camera as the quality and type of lens will
contribute greatly to the sharpness and overall appearance of the picture.
There are various camera lens types. The most common are Wide angle,
Standard, Telephoto and Zoom. Please refer to Lens Types to learn the
different uses and functions of each of these lenses.
The Camera Shutter: As previously mentioned, light enters the camera through the lens. However, the
light coming through the lens cannot reach the sensors until the shutter release button is pressed and the
shutter is opened. Once the shutter is opened, the light flows in and is exposed to the camera sensor. The
amount of time the shutter remains open is called the shutter speed. Shutter speeds are expressed as
seconds or fractions of a second. A 1/30 shutter speed means the shutter will be open for one thirtieth of
a second. A 1/250 shutter speed will keep the shutter open for one two hundred and fiftieth of a second.
Check the Shutter and Shutter Speeds tutorial to see why shutter speed is important.
The Aperture: The aperture controls the amount of light that will reach the camera sensor. (as opposed
to the shutter which controls the length of time light is exposed to the sensors). The lens aperture has
different size openings which are referred to as f-stops. A large aperture opening would be an aperture
setting such as f-2.8 or f-4 while a small opening would be set at f-16 or f-11. The aperture opening size
helps to determine how much certain areas of the image will be in focus or out of focus. Read the tutorial
about the Aperture for more details about its function.
Sensors and Pixels: The focused light coming through the lens is directed to the digital camera sensor.
That focused light is "captured" or read by the sensor prior to being stored in the cameras memory. The
sensor has a grid with millions of microscopic light information recording elements called "photosites".
Each one of these photosites are better known as pixels. One million pixels is equal to a Megapixel. Each
photographic image consist of millions of pixels. In general, the more pixels in a picture, the better the
quality of the image. For more on sensors, please read Digital Camera Sensors.
So to wrap things up, heres is what happens when you press the shutter release button. The light from the
lens goes through the aperture opening and shutter to be recorded on the camera sensor. The
information is then stored and reproduced as the image or "the picture" You can then view the image
right on your camera's LCD screen or download it to a computer to view or make prints. Simple right? Of
course the whole process is much more complicated and there are more parts working in the camera.
However, everything else that a camera might do revolves around making sure the above mentioned
functions are properly working together.
Easy Basic Photography
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