Quote Originally Posted by Michael R 1974 View Post
1.Situations where there is a lot of depth and multiple planes, and tilts and swings cannot be used:
·How do you decide where to focus?
·Do you use “conventional” depth of field rules?
·Do you focus on the near objects?
·Do you focus at a hyperfocal distance (ie focus on nothing)?
·Do you use Merklinger’s “object plane” method (usually resulting in an infinity bias)?
·Do you focus at infinity?
·How do you determine depth of field?
·Do you simply use the near-far focus method?
In this case you can't really use tilts or swings unless one plane is much more important than another. But in most cases like this I find movements make the image look weird. For example adding a swing to get a receding wall in focus works, but if the objects on other planes are out of focus at different distances it's odd to my eye. So in this case I either find the subject and focus on that and let the rest stay blurry, or I focus on the subject and stop down enough to bring the rest into focus. Sure diffraction will rob you of some sharpness, but you can still make a pretty decent 16x20 print from a 4x5 at f/32 or higher. Only if there are two subjects at different distances do I focus between them (about a 1/3 of the way, but I do this by feel of the focus knob, not direct measurement so it's rough).

I don't usually bother with DOF charts since all the lookups distract me and ruin the experience. I usually can see well enough on the ground glass with a loupe to know if I'm close. I then close down one more stop from experience. If in doubt close down more and deal with the diffraction blur later. I've learned the hard way that you can still get a good print when diffraction has blurred it (just at a smaller print size), but you can salvage a shot where there is awkward out of focus areas.

I almost never focus at infinity, as you are wasting a lot of DOF that could let you open up a bit. The one exception would be if the subject really is at infinity (and there is nothing closer), in which case you could shoot that at what ever aperture you want.

Quote Originally Posted by Michael R 1974 View Post
2.Situations where tilt can be used:
·How do you decide where to focus?
·Do you determine the tilt angle?
·If you use Merklinger’s methods and the hinge rule, how do you determine where the plane of sharp focus should be? How far below the lens should the hinge line be? How do you estimate all the distance measurements involved? How do you decide on the angle the plane of sharp focus should take from the foreground to the background? Etc etc (there are so many variables in this).
·How do you determine what lies within the depth of field? The math might work nicely on a diagram, but in the field how do you really figure out where things are in the space in front of you?

Thanks
I determine which plane I want to focus on when I'm not looking through the lens. This lets you see in three dimensions and spot things away from the plane that will look odd if they get blurry as you move away form the plane (think trees with blurry tops). I usually tilt the lens and determine it by eye making sure the plane is in focus both near and far. I then look at the camera from the side and check if it confirms to the Scheimpflug principle. If it doesn't I know something is wrong. I then stop down enough to make sure all the trees and other things are sharp to the tips. Remember to check the tallest/farthest objects from the plane (in reality picture a wedge going out along the plane). These will be where the problems are. And I stop down one stop to account for my eyes and the loupe, as above. When using movements I am almost always trying to get the whole scene in focus. If not I generally find things look odd.

I never bother with the math, and hadn't heard of Merklinger’s methods until this post. A simple visualization of the Scheimpflug picture works well for me. It's easy enough to see if you step to the side of your camera.