Differences Between Film and Digital

The modern, film-based single lens reflex (SLR) camera is a complex of electronics, mechanics, and ultra high-precision optics. A major part of its operation is concerned with winding-on and rewinding the film - in the camera illustrated here, a motor performs this function as well as controlling the mirror action. As you would expect, autofocus cameras require a further layer of complicated integration between the electronics, optics, and mechanics.

While a digital camera is no less complicated in its mechanical and optical construction, its electronics are far more powerful than you would find in a film-based model. A major saving is not having to transport the film -the design for a static photosensor is far easier than that for a moving strip of film. But nearly all other film-based camera operations are needed.

Image structure

Film
- silver grains or dye clouds of varying size distributed in a random pattern.
Digital
- same-sized sensor pixels arranged in a regular grid, or raster array.

Colour recording

Film
- colours in the scene separated by red-, green-, and blue-sensitive layers.
Digital
- colours in the scene separated by Bayer pattern of red, blue, and green filters.

Colour reproduction Image amplification

Film
- dye clouds of cyan, magenta, and yellow. Development by chemical action.
Digital
- interpolated from colour filter array. Electronic and digital processes.

Image quality

Film
- depends on film speed, grain structure, and processing regime.
Digital
- depends on sensor resolution and interpolation methods; also compression, if used.

Storage

Film
- image fixed by removing unexposed silver black and white stable, colour less so.
Digital
- image stored temporarily on memory cards or hard-disks.


Steve J. Wilson is living in the United States and is a freelance writer since 2006, in digital photography related topics. If you are interested in some useful Digital Photography Classes, than you are in the right place.

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