rule of thirds

The basic principle behind the rule of thirds is to imagine breaking an image down into thirds (both horizontally and vertically) so that you have 9 parts

As you’re taking an image you would have done this in your mind through your viewfinder or in the LCD display that you use to frame your shot.
With this grid in mind the ‘rule of thirds’ now identifies four important parts of the image that you should consider placing points of interest in as you frame your image.
Not only this – but it also gives you four ‘lines’ that are also useful positions for elements in your photo.

The theory is that if you place points of interest in the intersections or along the lines that your photo becomes more balanced and will enable a viewer of the image to interact with it more naturally. Studies have shown that when viewing images that people’s eyes usually go to one of the intersection points most naturally rather than the center of the shot – using the rule of thirds works with this natural way of viewing an image rather than working against it.

The photography rule of thirds tells us to align our subject with one of the points where those lines cross. That means our subject is one third of the way “into” the picture space – from either the top or bottom, and from either the left or right. And that means it’s not in the middle.
It is interesting to note that we refer to the most significant element of our image as the “center of interest.” The word "central” is a synonym for “important.” It comes as no surprise, then, that we instinctively place the subject of our image in the center of the frame. Bullseye! It’s only natural to line up the camera with what we are paying most attention to.
It takes some conscious thought and careful composition to place your center of interest off-center. However, the result is much more pleasing to the eye. Placing it at the intersection of the tic tac toe lines (also known as the thirds position) produces a nicely balanced image.

Central placement of objects is static. If an object is an equal distance from all sides, there is no implied need to move. The object is balanced, and therefore at rest.

There’s no tension, no tug in either direction. Now, this is where the photography rule of thirds becomes a guideline. If balance is what you are trying to express, then central placement of your subject may be just the way to go! In general, the idea is to divide up the picture space into areas in a 1:2 ratio (one third and two thirds), rather than equal halves.

The imbalance results in a more dynamic image. Following is another example where the picture space is divided horizontally into a one-third and two-thirds ratio: You can enhance the picture composition even more by creating a counterpoint. If you place your primary focal point at the thirds position, you can place a secondary focal point at the diagonally opposite thirds position, as in the following images. A natural extension to the photography rule of thirds is to place your horizon line along the one-third or two-third line of the tic tac toe grid, rather than in the middle.

Once again, fight your natural tendency! Without being taught otherwise, most amateur photographers will place their horizon in the middle. This ends up looking dull and uninteresting. Whether you place the horizon closer to the top or closer to the bottom of the picture space depends on which you want to emphasize more: the land or the sky. If you have a dramatic sky, by all means, give it two thirds of the picture space! You can “stretch” the photography rule of thirds for a more dramatic effect by placing your horizon (or your main subject) even closer to the edge of the frame