Mark’s medium format Fuji GFX 100S has 7 aspect ratios to compose images in the viewfinder: 1:1, 7:6, 5:4, 4:3 (native), 3:2, 16:9, 65:24 (pano).

Most full frame 35mm cameras still only offer 1:1, 3:2 (native) or 16:9. Some add 4:3 and/or 5:4. Panasonic S1R has 1:1, 4:3, 3:2 (native), 16:9, 2:1, 65:24.

iPhone only shoots in 16:9 and 4:3.