Fifteen seconds sounds like nothing. In practice it is enough for a complete emotional arc, provided the arc is built for that length rather than trimmed down to it.
The mistake is treating a short film as a compressed long one. Compress a thirty second story into fifteen and you get a rushed thirty second story. Build for fifteen from the start and you get something dense and complete.
Three moves, not five
A fifteen second film can hold roughly three moves. A world established. A turn or a reveal. A resolution that leaves something behind. Try to fit a fourth and every move loses its air.
The discipline is deciding which three. That decision is where most of the creative work happens, long before anything is produced.
Where thirty seconds earns its place
Thirty seconds is not fifteen with more shots. It buys atmosphere: time to let a room breathe, to hold on a face a beat longer than is comfortable, to let a viewer arrive at a feeling rather than being handed it.
Choose fifteen when the product has one clear thing to say. Choose thirty when the world around the product is the point.
