Art supply companies sell pre-stretched canvases, wood and hardboard panels with only a limited number of dimensions. Standard width/length ratios are 1 x 1, 1 x 2, 2 x 3, 3 x 4 and 4 x 5. If I want to use a photograph of my camera as a motif, a 2 x 3 panel would be the most suitable to represent the full picture. Musing on dimensions, the golden ratio came to mind – 1 x 1.618 – easy to remember because 1.6 km equal a mile.

Here is a photograph cropped to fit the golden ratio with respect to width and length:
1-x-1_618

The next image with a 2 x 3 ratio would require the least cropping of a photograph shot by my camera if the horizon had been horizontal. As it happened, the horizon had to be straightened in AP.
2x3

Next, a crop giving a ratio of 3 x 4:
3x4

Still closer to a square with a ratio of 4 x 5:
4x5

Omitting a square, the final image has a 2 x 1 ratio:
1x2

Do you spend much time deciding on the format for presenting a motif that you are interested in?