What is the Proportions?
Most cameras take rectangular pictures, so your first decision must be whether to shoot a vertical or a horizontal composition. Sometimes this choice is dictated by the proportions of the subject itself, or by how the result will be used (horizontal format for TV or computer screen, vertical to suit a show-card layout or magazine cover).
Of the two formats, horizontal pictures tend to be easier to scan, possibly because of
the relationship of our two eyes, or the familiarity of movie and monitor screen shapes.
Horizontal framing seems to intensify horizontal movements and structural lines ), especially when the format is long and narrow. In landscapes like that it helps increase the importance of skyline, and in general gives a sense of panorama, and of stability. Vertical pictures give more vertical ‘pull’ to their contents.
There is less ground-hugging stability, and this can give a main subject a more imposing, dominant effect. Vertical lines are emphasized, probably because you tend to make comparisons between elements in the top and bottom of the frame rather than left and right, and so scan the picture vertically.
Square pictures are entirely different and conventionally the square is used as a portrait format. Each corner of the square format tends to pull away from the centre equally, giving a balanced, symmetrical effect. Many photographers will avoid the square format but when used successfully it is very effective.
A predominantly vertical subject can be composed within a horizontal format, sometimes by means of a ‘frame within the frame’ – showing it within a vertical area naturally formed by space between trees or buildings, or through a vertical doorway, window or mirror. It is also possible to crop any picture to different proportions during enlarging, producing either a slimmer or a squarer shape.
Digital images can be cropped both in camera using the crop function/mode (not all digital cameras, mostly lower end of the market models, do this) or in post-production.
For many years some leading photographers felt strongly against any such ‘manipulation’, even to the extent of printing a thin strip of the film rebate all round the frame to prove it remains exactly as composed in the camera.