The circle of confusion is not a property of the lens itself. Rather, it is a m easure of how critical you, the photographer, want to be. Hyperfocal distance ( and, by extension, depth of field) will vary depending on how large a circle of confusion you consider to be "acceptable". The less critical you are (or the s maller the print size you want to make), the larger a circle of confusion you ca n use in doing your DOF calculations.

Kodak does put out a publication on optical formulas which includes the "standar d" COC size for different film formats. (Sorry, I don't remember what they are) . However, there is no such thing as the "correct" circle of confusion for a gi ven lens--basically, its whatever you can live with.