In its most basic form, a camera is a box that controls the amount of light to penetrate through an opening at the front. When this light enters the camera, it hits a light-sensitive material on the opposite inside surface. The hole may be fixed in size or variable, and the method for opening for opening and closing it might range from a simple flap to a tiny electrical impulse from a computer chip. Light sensitive materials might be a sheet of film or paper coated with silver halide emulsion used in film cameras, or an array of thousands or millions of charged couple devices (CCDs) used in modern digital cameras. For the purposes of this course we are going to focus on digital cameras since film cameras are becoming much less popular and difficult to get supplies for.

Whether extremely simple or highly sophisticated, a camera must accomplish one basic task - capture a picture. To do so, it must gather the light rays reflected from an object or scene and then focus them on a light-sensitive material. That material, in turn will be affected by the light rays and capture a representation of the scene. The CCD sensor used in digital cameras records it as a digital pattern of voltages that can be stored and then can be displayed on a screen or printed to paper.

A digital camera is made up of at least 3 interacting systems: viewing/focusing system, a light control system, and an image capture system.


Digital cameras are actually computers with specific functions and modes to influence image quality. For instance, you choose the file format, resolution, focus mode, exposure mode, shutter speed, aperture, white balance, ISO, and more. 

As a photographer, achieving ultimate quality images may well be the most challenging test you'll ever face, but the results can also be the most rewarding. With today's advanced digital cameras, superior lenses, and sophisticated software, there is enormous potential to create outstanding photographs. Digital cameras and LCD monitors help photographers to evaluate their photos on the spot, learn from their mistakes, and fine-tune techniques. These advances require dozens of decisions that impact the quality of a photograph.

Viewing / Focusing

Most modern digital cameras use some form of LCD screen to allow the photographer to see the image before it is captured. Being able to see the image before capturing it allows you to ensure it is in focus. Most digital cameras use auto focus but for more creative control it is better to turn that feature off so you can focus manually.

Light Control

To be a successful photographer you have to be able to control the amount of light reaching the cameras sensor. This is accomplished by 3 important settings; the aperture, shutter speed and the ISO. Each of these settings will be discussed in future modules.

Image Capture

Where older cameras used film to capture an image, digital cameras use an image sensor. The sensor size has a major impact on the quality of your image, how your lens functions, and how it performs in low light conditions.

This concludes the Introduction to the Camera section.  Please proceed to the next section, where you will learn about Camera Basics.