Before anything else the first thing you must do is wrap your head around aspect ratio. If you don’t do math well please don’t bail out and hope to absorb this some other way. Sooner or later the aspect ratio of a camera will effect you so get it over with now.
The aspect is simply the ratio of an image’s width divided by its height. It is usually expressed as whole numbers such as 4×5, but here I’ve expressed it as a ratio where the shorter length is figured as 1 such as 1:1.25. Do the math and you will see that 1:1.25 is the same as 4×5.
A full sensor 35mm camera uses a 24×36 mm sensor. A 35mm film camera takes a photo exposing a piece of film with the same size. The aspect ratio is 1:1.5 because 36 is 1 and a half times larger than 24. That means you can get a print 8″ x 12″ (or 12″ x18″ or whatever) from a 35mm file, negative or transparency. This confused me the first time I asked a commercial vendor for an 8″ x 10″ print from a 35mm format slide. His question to me was “where do I crop?” And that introduced me to aspect ratio in photography.
I asked for an 8×10 because that was very standard for portrait frames back in 1992. The 8×10 goes way back, kind of like Mr. Peabody and his boy Sherman. An 8″x10″ camera was the de facto negative standard a century or more ago. That is why 8×10 prints are still popular today. The 8×10 has an aspect ratio of 1:1.25. Thats because the 10″ side is longer by 25% than the 8″ side. Note the 1:1.25 is different than 1:1.5.
Of course there are other standards, 4×6, 5×7, 11×14, etc. If you go back to the 1930s you find square medium format film cameras became very popular along with other sizes that are barely used today. The square medium format films have a ratio of 1:1. Why? Because they shoot a square piece of film where the width and height are the same! What good is this you say? Wedding and event photographers loved this format. It allowed a crop horizontally or vertically from the same piece of film. Another popular 1:1 found its way into a some consumer cameras of the 60s. It gave the user a 40 mm x 40 mm negative or slide.
On to the market in early 2011, Fuji has a new camera for sale, the HS20EXR. It is a fixed lens digital camera. It offers 3 different ratios, 1:1.333, 1:1.5, & 1:1.778. The last one is better recognized as 16:9. In the camera all of the formats use the longest width of the sensor. To get the other formats the camera uses a different set of height pixels to make the ratio. The dot density and the 1.333 size make it almost perfect for an 11×14 print. The 1.778 (16:9) makes it perfect for video. I’m not trying to sell the camera to you, but I am trying to make you think about the size of the print you want.
There were many, many ratios in the film past, and some were quite popular with photographers. I won’t cover them all here, but some of the ratios were 1:1.167 (6×7 centimeters), 1:2 (6×12 centimeters), 1:1.333 (4.5×6 centimeters and 6×8 centimeters), and 1:3 (6×17 centimeters). Another interesting one was the 6×9 centimeter format. What was its ratio?
Click on the photos above to see the differences! They are all horizontal examples. The ratios are the same if the photo is vertical.