effects due to the random orientation of grains.
Estimates of the resolution of a photograph taken with a 35 mm film camera vary. However, there exist many estimates around 12 megapixels.[2] [3] It is possible for more resolution to be recorded if, for example, a finer grain film is used or less resolution to be recorded with poor quality optics or low light levels. The analysis of R. N. Clark leads to this conclusion: "The digital megapixel equivalent of film is highly variable and roughly depends on film speed. Slow, fine-grained 35mm films with speeds of ISO 50 to 100 have megapixel equivalents of 8 to 16 megapixels. ISO 400 films are only around 4 megapixels." This would place top-of-the-range digital cameras (as of 2006) well over 35 mm film cameras.
It should be noted that a special case exists for long exposure photography - Currently available technology contributes random noise to the images taken by digital cameras, produced by thermal noise and manufacturing defects. Some digital cameras apply noise reduction to long exposure photographs to counteract this. For very long exposures it is necessary to operate the detector at low temperatures to avoid noise impacting the final image. Film grain is not affected by exposure time, although the apparent speed of the film does change with longer exposures.
Convenience and Flexibility
This has been one of the major drivers of the widespread adoption of digital cameras. Before the advent of digital cameras, once a photograph was taken, the roll of film would need to be finished and sent off to a lab to be developed. Only once the film was returned was it possible to see the photograph. However, most digital cameras incorporate an LCD screen which allows the photograph to be viewed immediately after it has been taken. This allows the photographer to delete unrequired photographs and offers an immediate opportunity to re-take. When a user desires prints, it is only necessary to print the good photographs.
Another major advantage of digital technology is that photographs can be conveniently moved to a personal computer for modification. Many digital cameras are capable of storing pictures in a RAW format which stores the output from the sensor directly rather than processing it immediately to an image. When combined with suitable software, such as dcraw, this allows the user to configure certain parameters of the taken photograph (such as sharpness or colour) before it is "developed" into a final image. More sophisticated users may choose to
