The Traveling Head - Frame-by-Frame Stop Motion: The Guide to Non-Traditional Animation Techniques - page 163

The distance from one position to the next, once you get past the ease-ins,
is determined by how fast you want your subject to travel and how
rapidly you want your backgrounds to change. Naturally, the bigger
the position change (i.e., 10 feet), the more rapidly your character
travels. Bigger moves are very effective outside, because you have large
environments. But I recommend that you move your subject about 3 feet.
This works well for going from the house to the mailbox or even around
the block, but the longer the distance, the longer your film is based on
a 3-foot move per frame. If the background changes too radically frame
to frame, then you might start to lose the effect of forward movement. It
is most effective if the background displaces itself at an even rate, so we
see background elements diminishing in the frame, indicating that we are
moving past them.
ExErcisE Fig 1.c A series of frames showing how the background changes.
So, you start with your human subject lined up in front of the camera in a still
position. I find that it adds a lot to the film if you try to give your human
subject some expression of thought or, perhaps, determination. Remember
that you have to break down these expressions bit by bit, and the extreme
or “key” expression should be strong and slightly exaggerated. Your human
subject also needs to be able to hold that expression for long periods of
time. Be aware of what the eyes are doing. You can begin by just slightly
moving your camera on the tripod backwards by about an inch. Move up your
human subject to the camera that same inch distance so the relationship of
the camera position and human is always consistent. This is the first ease-in
movement of your journey.