Of course, while the stock -- and usually correct -- answer is that you need only a few degrees of tilt or swing, there are exceptions. This spring I found a Trillium in bloom that I had missed several springs before, and determined to make it into a photograph. Here's the camera as set up for the shot; I regret that I didn't measure the amount of tilt used as it was a lot; front tilt almost to the limit of the image circle (Caltar II-N 150mm f/5.6) plus back tilt to make up the difference, plus swings to tilt the focus plane into the hillside:



Access to the groundglass for composition and focusing was only by bending over at the waist and viewing it with my head sideways. After 45 minutes of tweaking the plane of focus, then waiting for the light to cooperate, I'm not as impressed with the result as I was with the visualization:



With all that, and even at an insanely small aperture, the fern frond that hangs down just above the flower was not nearly in focus. As shot, the trillium was about 1/4 of lifesize. In a normal world, that would make the foreground underexposed, but here the forest cover in the background was so thick that the background was the problem. In retrospect, I'd like the image better if I'd done some serious gardening to remove the dead stuff in the middle foreground. Philosophically, I have trouble with doing any more than minimal removal of the occasional stray stick, so the detritus was included. Like most hunting, the thrill is sometimes in the chase....