How Do Digital Cameras Work?

Film and digital cameras work the same way in most parts, except digital cameras use CCD or CMOS instead of film. Light passes through the lens and exposes the film in traditional cameras. We use films with different color balance and sensitivity to light, depending on the situation or our own personal preferences. Exposure is controlled by changing the aperture and shutter speeds. Digital cameras work the same, except instead of film, the CCD is charged up and gets ready for the picture to be taken. Light enters the camera but instead of exposing the film as in 35mm cameras, it strikes the CCD. Image is kept temporarily in an internal memory called the buffer and then compressed to JPEG or RAW format and then stored on the memory card. This process can take a few seconds to complete before another picture can be taken. More sophisticated cameras have larger buffers that can hold several high resolution images to allow continues shooting. Canon EOS-D30 for example, allows up to 8 frames to be taken in continues mode while the EOS-D1 can be used for up to 21.

Unlike films which are designed for certain type of situations such as daylight, tungsten, or infrared photography, digital camera CCDs cannot record the color of light. Both film and CCD receive light that hits them and exposure is calculated based on the ISO used. Color is recorded based on the type of film used in film cameras. Daylight balanced films do a good job of recording colors in daylight under most conditions. Color balance is set by the film manufacturer of films. We use filters to further adjust colors if necessary. Digital camera sensors work differently. CCDs have millions of sensors that record the amount of light, not the color of light. Color filters over sensors are used to detect colors in each pixel. All colors in each sensor is then calculated to form a final image.

Digital cameras use white balance controls to adjust color balance. Color correction filters are not needed. Instead, the camera automatically senses the color temperature and adjusts accordingly. You can also set the white balance manually. This is important for many situations. Film and digital cameras are tools. They have no idea what a scene is supposed to look like. They can guess and give good results some of the time. For instance, colors in sunrises and sunsets record differently on different types of film. Light changes rapidly which affects colors every few seconds. What the film sees is not what human eye sees. This is why our sunrise and sunset pictures never look exactly the way we saw them. If you know your film's characteristics and how it reacts under certain lighting situations, you can control the light to get the result you want by changing your exposure and through filtration. In digital, the white balance control is used to adjust colors. By setting the white balance to daylight for example, you can photograph sunsets that look warmer than if the camera was set on auto white balance. In automatic white balance mode, camera wants to make the light neutral. By switching to different white balance modes, you can get results closer to real life without having to add filters.

All the things mentioned here are what you need to know about how digital cameras work and how they differ from film cameras. Photography is still the same. Choosing lenses, exposure, composition, etc. You also need to know about resolution and what your image editing software is capable of doing once the images are downloaded to the computer. Unless you know how your camera works, it is not possible to have full control over your photography. Just take some time to learn more about your camera and how it works. This may not be fun but will improve your photography.