The purpose of this rule is to redirect the attention of the photo away from the center causing a more stimulating and unique perspective. To achieve the rule of thirds, mentally picture the image is divided up into nine equal parts: two equally spaced vertical lines and two equally spaced horizontal lines. Now, arrange the focus of your point of interest (specific compositional element point or basically whatever it is that is your main focus point) so that it falls on at least one of the lines. The frame is literally being divided into thirds, hence the rule of thirds
I included the desired line arrangement in the photos within the post
Demonstrating with the difference below- the image on the left applies the rule of thirds unlike the one on the right, which doesn’t. The focus point is directed towards the center (the opposite of what were going for). The same picture grabs more attention when keeping the rule of thirds in mind.
Example ~ when capturing a landscape: it should be laid out using the rule of thirds as two thirds of one element (water) and another separate element (land) taking up the space in the other third. (Ratio = 2:1)
“Favored by cinematographers in their effort to design balanced and unified images.”
-Michael Ryan & Melissa Lenons
*I recently found this app “Ro3 Free” which inserts the lines for the user (because many find this takes some getting used to, I recommend using this until it becomes easy to imagine them)
Rule of Third Examples: