Nathaniel Paust , Jul 15, 2001; 05:12 p.m.
I could be wrong, but my calculations suggest that it really doesn't matter which focal length lens you use for doing close-up work. For example, a 150mm lens will give you more DOF than a 210, but it will have to be closer to the subject. In the end, you end up with exactly the same DOF for a given f-stop.
The only way to get around it is to stop WAY down or use whatever tilts and swings are possible with your setup