I'm surprised these haven't already been mentioned:

http://www.largeformatphotography.in...-to-focus.html
http://www.largeformatphotography.info/fstop.html

I find the method described in the second article (How to Select the f-Stop) best for me. I have equipped my field cameras with millimeter scales and have taped a table of optimum f-stops to the camera body. Focus near-far, split the distance, set the f-stop based on the spread and shoot.

This I modify a bit when the horizon is in the scene and things at infinity are important. In this case (as per Merklinger's advice), I cheat toward the infinity a bit, focusing about 20% farther back (shorter) than halfway. Sometimes I'll use a bit smaller f-stop in this case as well.

For swings and tilts you use the same method with one caveat. When you reposition the plane of sharp focus with swings/tilts, the objects that are optically nearest and farthest in the scene are often counter-intuitive. For example, when using tilt to get a foreground object and a mountaintop in focus, the base of the mountain (even though it's physically closer) will become the farthest from the plane of focus. It takes a bit of practice to learn where the best positioning of the plane of sharp focus is for complex scenes. One way to tell if you have an optimum positioning is to measure the focus spread for various amounts of tilt/swing. The position with the least spread is the best and can use a larger aperture for the same amount of sharpness, which is usually more desirable.

Hope this helps,

Doremus

www.DoremusScudder.com