180-Degree Shutter

What this is about

This is the default motion look of narrative film: enough blur to connect frames smoothly, little enough to keep detail. Crews treat it as the baseline and note every departure as a creative event. Famous departures prove the point — a 45-degree shutter gives combat scenes their jittery harshness; wider angles smear light trails through night work. Because a shutter change reads instantly on screen, the decision belongs to the DP and director together, planned per sequence, communicated to the DIT, never left to a camera menu default.

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:

• It is a rule of thumb with a mechanical origin, not a law — the point is consistency, then deliberate deviation.
• Narrower than 180 sharpens and hardens motion; wider softens and smears it.
• Check the rule against local mains frequency: 50Hz countries often shoot 172.8 degrees at 24 fps.

With TillyGen

In TillyGen a sequence shot off the 180-degree baseline carries its shutter note through shot list and schedule, so no setup silently resets to default.

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.