Can I control depth of focus (v depth deph of field) I'm creating some studio-shot style images of products. I'm trying to get the foreground elements in focus while having the background blur slightly.

I've done a lot of real world studio photography and I know that depth of focus and depth of field are two different parameters (though frequently confused). Put simply, depth of field references the precise centre of the plane of focus as parallel to the image plane, while depth of focus reference the sum of the distance on either side of this plane that remains in focus.

But 2.6x only seems to offer control of the depth of field, so that only that exact plane is in focus, and everything either side gradually defocusses. Or am I missing something?

The point is, I want to know if there is a way to control the z-depth of the area in focus, not just it's distance from the camera.
You can find it under the camera property.
Select the camera and go to the camera tab.
There is a panel named &quot;Depth Of Field&quot;. Either select an object to be your focal point or set the distance.
Set Focal length and radius (f/stops) to adjust the depth.
Here with Radius 0.06

...and here with radius 0.3

From one photographer to another, as you know the Focal length and f/stop produce the DOF effect. Same in Blender where F/stop is better expressed in radius.
You can of course use F/stop instead of radius but don't forget to change the focal length, otherwise you will have to use ridiculously small F/stops. :D