Framing
Aspect ratios, and why the crop decides the composition
9:16, 16:9, 1:1 and 4:5 are not the same shot at different sizes. Each one demands a different composition.
01
The crop is not a container
Shooting 16:9 and cropping to 9:16 does not give you a vertical video. It gives you a horizontal composition with two thirds missing, which is why so much repurposed content feels wrong without being obviously broken.
A vertical frame has room for one subject and a lot of height. A horizontal frame has room for a subject and its context. Those are different pictures, and they need to be composed differently from the start.
02
9:16 — the platform eats the edges
On Instagram Reels, TikTok and YouTube Shorts, roughly the top 12% and the bottom 15% of the frame sit under interface: the caption, the account name, the action column on the right.
Compose for the middle. Keep the subject inside the central 70% of the height and clear of the right edge, and treat the top and bottom as areas that will be covered rather than areas you can use.
03
4:5 — the quiet performer
4:5 takes up more vertical space in an Instagram feed than 1:1 without going fully vertical, which makes it the most efficient ratio for a feed post. It also crops more forgivingly to 1:1 for a grid thumbnail than 9:16 does.
If you are producing one asset that has to work in a feed and in a profile grid, 4:5 with the subject centred is the safest single choice.
04
16:9 — context and scale
Horizontal remains right when the point is the environment: landscape, architecture, a wide showing scale, anything where the relationship between subject and surroundings carries the meaning.
It is also still the correct ratio for anything that will be watched deliberately rather than scrolled past — a YouTube video, a site hero, a presentation.
05
Tell the generator, and mean it
Most video models take the aspect ratio as a parameter, not from the prompt text. But the prompt should still be written for the ratio you set — a prompt describing a wide establishing shot with a small figure in the distance will not work at 9:16, because there is no width for the distance to exist in.
Every prompt in this library lists the ratios it was written for. Using a different one is fine, but expect to adjust the composition notes.
