... blog post:
I have a preference for squarer formats, like 6x6, 5x4, 4x3 and a dislike for the "letter box" ones like 3x2, 3x5 and 16x9 which I find too long and skinny to be able to frame subjects naturally thus often end up cropping them later in post.
Having tried them all, my favourite has become the 4x3 which, conveniently, is the format (aspect ratio of 4:3) of good old MFT (micro four thirds). Square-ish but not perfectly square it is brilliant for framing architecture for example where you need both height, width and depth i.e a sense of space, in the scene.
It is also fabulous for natural subjects such as trees in portrait orientation without having to stand back to include everything at the sides, then crop the top or bottom of the picture afterwards as I would if I were using 35mm so called full frame for example to get rid of the resulting extraneous bits included in the frame.
Wildlife seems to sit perfectly into the 4x3 frame too.
For me, 4:3 is the ideal aspect ratio for most types of photography and the the one I use the most which is one of the reasons that helps explain why I am so much at home with MFT format maybe.