The shape of a photograph is measured by its Aspect Ratio. This is the ratio of the width of the photograph divided by its height. Until smartphone cameras, the overwhelming majority of cameras used a ratio of 1.5 (width versus height being 3:2). This was the film format of “35 millimetre” (35 mm) cameras.
35 mm cameras were an offshoot of the movie industry. In the 1890s that fledgling industry standardized on that size of film. But the film was difficult to manufacture. Each batch was slightly different and had to be tested for its exact light sensitivity. Oskar Barnack, an engineer at the German company Leitz developed the Leica camera to do exactly that. But people loved that camera not just for testing movie film. They loved it just for taking still pictures. Other companies copied Leitz and produced cameras to use the same film. 35 mm cameras became hugely popular.
Other cameras were also made, mostly with much larger film sizes, to give higher quality images. These were called “large format” cameras and usually had an aspect ratio of either 1.25 (5:4) or 1 (1:1).
Even when most cameras became digital instead of film, the 35 mm aspect ratio of 1.5 was kept. However, most cellphones use an aspect ratio of 1.33 (4:3).
So the question arises: what is the best aspect ratio? The answer is that there is no single aspect ratio that’s best for all pictures. Photographers get to crop images and can, and do, choose different aspect ratios for different images. And “standard” print sizes have different ratios. The most common print sizes are:-
4x6 inches – Aspect ratio 1.5
5x7 inches – Aspect ratio 1.4
8x10 inches – Aspect ratio 1.25
11x14 inches – Aspect ratio 1.27
16x20 inches – Aspect ratio 1.25
An argument is often made that the most pleasing aspect ratio is 1.618033988749894... This is called the Golden Ratio. It’s related to the Fibonacci sequence of numbers, where each successive number is the sum of the previous two, i.e.
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, …
The ratio of successive pairs of this sequence gets closer and closer to the Golden Ratio.
Curiously, this ratio is frequently found in nature. For example, one can construct a spiral using squares with sides equal to the Fibonacci series, as shown below.
The Golden Ratio can also be found in art and architecture, whether consciously incorporated into the design or whether it is just a reflection of pleasing design.
The Parthenon on the Acropolis in Athens, Greece has several elements reflecting the golden ratio.
The composition of Michaelangelo’s Creation of Adam also follows the Golden Ratio.
Finally it seems that the golden ratio was intentionally included in the design of Toronto’s CN tower. The ratio of the total height (553.33 meters) to the height of the observation deck (at 342 meters) is 1.618.
