What he's talking about is partly an optical effect caused by the enlargement of the image in different formats. Consider three film cameras--a 35mm, a MF, and

What he's talking about is partly an optical effect caused by the enlargement of the image in different formats. Consider three film cameras--a 35mm, a MF, and a 4x5 LF camera, each with a lens that covers the same angle of view. That means that for a given film, the small format is compressed relative to the larger format--less film is used to capture detail and tonal variation. An object covering 2mm of film in one format may be covering 10mm of film in the larger format, but the film itself has the same amount of grain per mm in either case. It may be difficult to make a direct comparison to digital, since pixel size and density vary so much across cameras, and those variable have a somewhat different affect on picture quality.