Most of us are shooting a 3:2 aspect ratio which is equivalent to a 35 mm full frame sensor or film. Some micro four thirds and point and shoots use a 4:3 aspect ratio. Common cameras do not come with a native 1:1 aspect ratio, but here are a few good reasons to shoot 1:1 or crop 1:1.
After putting our subject dead center into a photo, we learn to use the rule of thirds which works great in landscape and portrait orientation in a 3:2 ratio photo (see our popular blog post about the rules of thirds).
However, there are many circumstances where a 1:1 ratio or square works best with the subject dead center.
My favorite use is portraits. Almost all portraits I make now with 1-3 people, I use a square photo. Sometimes 4 or more people is hard to crop into a square, but if I can do it, I will.
A square focuses the subject to the middle, catching our eyes. It also eliminates distractions to the side and behind the intended subjects.
Finally, I can darken the edges easily to focus even more on the subject.
With most cameras now, you can change the aspect ratio while shooting. If you want more options, shoot in 3:2 and then crop to 1:1 when you process the photo. Don’t worry about the lost pixels, they weren’t doing much for you anyway. Next time you are doing portraits, think 1:1 or a square. You will love the outcome.
To see more of(and buy) our photos, please go to www.pamphotography.com.
pamphotography 
I love squares!
We do too! Andrew Gibson wrote a good e-book on “the square” – its what got me started playing with this format
http://www.andrewsgibson.com/blog/square/