Originally Posted by
DanK
The "no cropping" idea, which is still surprisingly common, is the least sensible of all. The aspect ratios used in cameras vary and are for all practical purposes arbitrary. In FF and APS-C cameras, for historical reasons, it's 1.5:1. In MFT and many medium format cameras, it is 1.33:1. Back in the days of 120 film, camera manufacturers produced cameras with aspect ratios ranging from 1:1 to 4:1. One common was 6 x 7, 1.2:1, simply because that matches 8 x 10 paper, which is itself arbitrary and is an aspect ratio not found in most of the world today.
So, suppose you take out your FF camera and carefully compose an image. And let's say that by chance it happens to match the 1.5:1 aspect ratio of that camera. then suppose that you decide you want to use your medium format camera instead. Would the ideal composition change?
This isn't an entirely irrelevant issue for me, as I normally use 1.5:1 cameras but often travel with an MFT with a native 1.33:1 aspect ratio. The MFT has on option to change aspect ratios; it will also do 1.5:1 and 1:1, but at the cost of losing pixels. So, after I bought it, I thought hard about how often I leave the entire 1.5:1 frame uncropped on the long side. The answer was not all that often. So, I usually shoot the MFT in 1.33:1 (4:3) to maximize the pixels on the image that I want.