Close. DOF is determined by a combination of focal length and diaphragm opening diameter (aperture).
All 150mm lenses @ f8 have the SAME dof (providing for minor variations because of varying lens designs). It doesn't matter if the coverage of the lens is for 24x36mm or 6x7cm or 4x5in. 150mm is 150mm and f8 is f8. Period As a photofinisher I must disagree. Technically only 1 point is in actual focus, everything else is increasingly out of focus (circle of confusion). So as you enlarge further, less area is perceived to be in focus. This is why I usually will use the guide for 1 F stop more open when using hyperfocal distance. So, although a 150mm lens is a 150mm lens, unless you are shooting film that you are not going to print (enlarge) then both format size( needs more/less enlargement for any given print size ) and print size contribute to what is perceived to be in focus, which is what depth of field is supposed to measure.
