Why does 35mm film have lower quality ratings than the dpi would suggest?
The resolution of film cameras is based on the resolving power of the film itself, not the resolution at which it was scanned. It is possible to scan a 35mm film at 10,780 dpi for a file of 10187×15275 pixels, but that does not mean it will have the same quality as a digital sensor of the same dimensions. Color slide film such as Fuji Velvia 50 or Provia is generally accepted to have a resolution of about 5000 dpi, but the actual amount of detail recorded can vary depending on the lenses used. Because of this a scanned pixel from film is not an exact equivalent of a pixel on a digital sensor, and we have given quality ratings for 35mm film based on our experience of how they translate to the sizes in the chart.
