Dear sir,
I am forwarding a site address for the reference of forum members
DOF in which it is made clear that the DoC does not depend upon the size or media. I am reproducing a paragraph from the article for the ready reference "Digital Vs. Film, and What About Medium & Large Format
There was a query in October, 2001 on my Discussion Forum as to whether Depth of Field was calculated any differently for digital Vs. film. The answer is, no. There is no difference whosesoever. DOF doesn't care about the recording media type or size, though a lower COF is used for medium and large format, since the amount of magnification to make a decent sized print is much less than for 35mm".
I think the science behind is clear to members of the forum
Chandrashekhar