Aspect ratio
Beeldverhouding · Composition
The ratio of the width to the height of a photo, such as 3:2, 4:3, or 1:1.
35mm film and most DSLRs use 3:2. Micro Four Thirds uses 4:3. Instagram popularized the square (1:1). For video 16:9 is standard. Aspect ratio affects composition: a portrait looks different at 3:2 than at 4:5 (Instagram portrait format).
Tools that help with this: