[Excerpted from the FAQ, that’s rapidly becoming obsolete, but I’m saving this info here.]
Theoretically, no, but practically yes.
First, “depth of field” is an approximation. It’s simply the volume adjacent to the plane of focus where the circle of confusion is small enough to appear sharp at some combination of print size and viewing distance. The circle of confusion is in its turn dependent on the imaging area’s makeup and size.
The equations for calculating depth of field use focal length, aperture, and circle of confusion. Imaging surface size has no impact (except on CoC, as mentioned above). Its apparent affect on the DoF is simply due to the fact that different focal lengths are needed for each imaging surface size to maintain the same field of view.
Here’s a practical example. Say you want to shoot a subject from 3 metres away. You have 3 bodies, a crop DSLR (APS-C sensor), a film body (or “full-frame” DSLR), and a 6x6 MF body. The normal lenses for these bodies are 28mm, 45mm, and 80mm respectively.
This table shows the depth of field for two apertures, ƒ/2.8 and ƒ/8:
| Lens | Circle of confusion (mm) | ƒ/2.8 | ƒ/8 |
|---|---|---|---|
| 28mm | 0.02 (digital sensor) | 1.34 | 5.75 |
| 45mm | 0.033 (135 film) | 0.83 | 2.75 |
| 80mm | 0.053 (120 film) | 0.41 | 1.21 |
More information about depth of field can be found in this tutorial at Cambridge in Colour.