Adjusting the focus point - 1/3 in or half way?
OK - I have read Quang-Tuan Luong's article 'How to focus the view camera' http://www.largeformatphotography.info/how-to-focus.html and I am a little confused regarding placement of the focus point.
In procedure 1 he begins by saying - 'when you establish a Scheimpflug relationship, the subject plane (plane of focus) is one where depth of field behind that plane remains double the distance of depth of field in front. This is just as when the subject plane is parallel to the film. If your camera is on top of the rock, you would have the subject plane defined by one point about two thirds of the way up the rock, the other two thirds the way up the mountain'.
This makes sense to me, if DOF behind the plane is approx double DOF in front of the plane then focusing 1/3 into the subject should place the plane optimally, indeed I have seen many various references advising to 'focus 1/3 in' to make best use of DOF.
But in procedure 2 he talks about adjusting the focus point by focusing on the closest and furthest points and adjusting the plane so that it's midway between the 2 points. Again I have seen many various refenences advising this method including Leonard Evens http://math.northwestern.edu/~len/photos/pages/dof_essay.pdf
I know I'm simplifying things and the rules change if ininity is involved and for close ups but am I missing something here? - why do some reference 1/3 and some reference 1/2 ? If making the closest point and the furthest point equally sharp is optimal (provided the far point is not at the horizon), why does he advise defining the subject plane as 2/3 up the mountain in procedure 1 and not 1/2 way up?
Also where does the hperfocal technique fit into this? where does focussing hyperfocally place the plane? is it closer to 1/3 way in or 1/2 way in?