Differences between Film Based and Digital Cameras

The main and fundamental difference between the traditional film based cameras and digital cameras is the method of capturing the image and how it is stored.

Traditional film based cameras use photographic film which is fed through the internal film transport system, which positions the frame to be exposed directly behind the camera’s lens assembly.

Once the shutter button is pressed the mirror flips up (blanking out the viewfinder) and the light from the subject and their environment enters the camera, controlled by the shutter speed and the amount by which the lens’s aperture is open, and this light hits the unexposed photographic film.  This action exposes the film, which is then wound on to the next available frame (unless it is held in position to be exposed again in the case of a multiple exposure).  The amount of light required to produce a correctly exposed photograph is also controlled by the film speed or ISO, the lower the ISO, e.g.. 25, the more light is required, but the higher quality photograph, the higher the ISO, e.g.. 1600, the less light is required, but the photograph suffers because of the size of the grain on the film required to capture the available light.

In the above example we can see that the image is recorded on the photographic film, which then has to be developed before the photograph can be seen.

On a digital camera the process is very similar:

Once the shutter button is pressed the mirror flips up (blanking out the viewfinder) and the light from the subject and their environment enters the camera, controlled by the shutter speed and the amount by which the lens’s aperture is open, but this time the light hits the camera’s sensor.  This time the pixels on the camera’s sensor measure the amount of light and its colour and tone and records this information internally in a digital RAW format.  The photograph is then processed within the camera and output to the memory card in the format and quality settings as set up in the camera.  Again the amount of light required to produce a correctly exposed photograph is also controlled by the ISO, but as there is no photographic film the camera’s sensor handles the different amounts of light, but like the traditional film photograph, which suffered because of the size of the grain on the film required to capture the available light, in the digital camera the lower light levels can cause noise (a digital form of grain).

In this example the photograph was recorded by the camera’s sensor and stored on the memory card, which unlike traditional film, is re-useable.