Depth of Field

What this is about

Four levers move depth of field: aperture, focal length, subject distance and sensor size. On set the choice is rarely free — a shallow T1.5 close-up looks expensive but hands the focus puller millimeters of tolerance, which means rehearsals, marks and more takes. Action and stunt work gets stopped down for safety margin; dialogue scenes open up for separation. Directors decide what the audience may see sharp; the AC department pays the bill for that decision in concentration.

A term only helps when everyone on set means the same thing by it — so what follows is how it is used, not a dictionary definition.

What runs differently here

Where this differs from the general case:

• Roughly one third of the sharp zone lies in front of the focus point, two thirds behind — a rule of thumb, not a law, and it collapses at close range.
• Shallow focus raises the blown-take rate; schedule extra takes when shooting wide open.
• Sensor size changes depth of field only through the lens and distance you pick for the same framing.

With TillyGen

In TillyGen a shot marked wide-open and close gets flagged as a slow setup in the schedule, so the day plan absorbs the extra takes.

Change one constraint and the consequences travel through the whole plan: affected shots are flagged, the call sheet is regenerated, and nobody keeps working from yesterday's version.