Quote Originally Posted by StoneNYC View Post
Well also, this was used for 35mm movie film, which isn't 24x35 because the image is made "vertical" on a spread out film strip rather than horizontally. So really it's an APS size area that needs to be hit, so that probably helps with the 0.70 right?
The depth of focus is only dependant on focal lenght and aperture, not on image size/format.

(I leave aside the issue of enlarging and circle of confusion.)

Furthermore Kubrick used the lens on a viewfinder camera. Focussing was most probably done done by means of tape.