Aspect Ratiotechnical
The shape of the frame — the ratio of width to height, like 3:2 or 1:1.
Full-frame and APS-C sensors are usually 3:2; Micro Four Thirds is 4:3; square is 1:1 (popular on social); 16:9 is cinematic/wide. You can shoot a wider ratio and crop, or compose for a target ratio from the start. Different ratios suit different subjects — 1:1 for tight portraits and product shots, 16:9 for sweeping landscapes.
Use this when
- Most cameras: 3:2 native
- Social / portraits: 4:5 or 1:1
- Cinematic landscape: 16:9
Common mistake: Cropping to a new ratio after the fact and chopping off the subject.