The third day of shooting was more of a travel day with a magic hour shot at the end of it all. We headed out of Austin towards Henrietta, Tx with a loaded equipment truck and numerous cups of coffee. After arriving at the cabin we were staying in, we all loaded up into a jeep to go on a safari style location scout for the places we'd be shooting at in the next couple days.
The only shot slated for the day was a sunset shot of an actor on horseback riding up towards the camera, stopping and staring into the distance. Simple enough, so we put the Panavision GII on high sticks, set some marks, took a meter reading and were good to go. But wait! (and there's always something that you have to do before you roll) I had to get a measurement of the focal distance.
If you've ever worked with or been around horses you know that they don't like fast movements or strange things around them especially when they make weird noises (like a tape measure). So after avoiding that mishap with the actor/horse, I took a quick measurement to the mark they were supposed to hit - compensated for the added height of the actor on the horse and was ready to roll.

This is the best chart I could find off hand, but basically to read it you look at the following. Look at you f/stop, lets say f/2. Then find your focal distance, 14 ft. So then what it says is that your Acceptable focus on a 35mm lens at f/2 at 14 feet is from 12.7 feet to 15.6ft - around 3 feet depth of field. Of course you want everything to hit the marks, but this tells you your wiggle room or how focal depth will play out on the processed film (for stylistic choices). There is also a Hyperfocal distance (which this chart did not include) but the Hyperfocal distance tells you that from half of that distance to infinity will be in focus. Just throwing that in there (without getting into circles of confusion etc which is a good discussion to have - so maybe someday..).
+john