>> |
Anonymous
A grain size of 1.5 micron gives the maximum resolution of 300+ megapixels. HOWEVER, a single grain can be either exposed or not exposed - i.e. either pure black or pure white for B&W film. So this resolution can be achieved only on black-and-white (not even grayscale) test charts and documents. For the same reason, a direct comparison between film and digital is not possible - one photosite of a 20 MP full-frame sensor is about 6 microns in size - thus 16 times larger than the finest grain of film - but it can resolve lots of different shades (up to 4000 for 12-bit ADC and 16000 for 14-bit, if we discount noise), not just pure black and pure white. Also, grain size in film is more or less proportional to its sensitivity. If ISO 50 film resolves 300 megapixels, ISO 1600 film of the same kind will 32 times less - around 10 megapixels, and that's only on a pure black and white test chart, as mentioned earlier.
|