The PRINCIPLES OF COMPOSITION are the rules of grammar of the visual language of photography. The PRINCIPLES organize the visual elements into a pleasing and comprehensible whole. This organization is called COMPOSITION. Our first response to a composition is to perceive it as a whole. This response is subjective. Strong images feature many of these PRINCIPLES and/or emphasize a few.
UNITY is the quality of cohesion that makes an image feel complete or whole. Photographers achieve unity by using consistent methods to reveal the meaning, purpose, and/or the intention of their images. Distinctive ways of creating unity are often identified as artistic styles.
BALANCE refers to the distribution of visual weight in an image. "Empty" areas should not appear to be blank. Instead, they should represent void, or negative space. Likewise, positive shapes and forms should not appear to be too crowded, heavy, or busy. Balanced images may suggest motion, but it should not appear to be so unstable as if to suggest it would hang crooked.
MOVEMENT or visual movement is used by photographers to direct the scanning behavior of the eye along a circuit or path within an image. This circuit leads the viewer to areas of visual interest, focus, and/or emphasis. Motion is suggested by the action line of the subject in an image. The action line moves in the apparent direction that the subject is moving or looking.
RHYTHM is the sequencing or repetition of visual movement presented by the composition of visual elements: colors, shapes, lines, tones, forms, and textures. Variation and contrast keep rhythm interesting and dynamic.
FOCUS is the emphasized form or area which draws attention and reveals the subject, central idea, or theme of an image. Emphasis is often achieved by using rhythm and movement to lead the eye to an element that is unique, or has a contrasting tones, shapes, sizes, or colors. Focus and contrast are the same principles as emphasis and variety. In photography, selective focus can be optically achieved with our lens.
CONTRAST is the organized interplay of visual differences which provides variety and stimulates visual movement. Contrast refreshes the eye and enables the viewer to better perceive and evaluate the relationships between the visual elements.
PATTERN is a system of elements which creates a recognizable sequence of repetition. Pattern may also be thought of as the underlying structure, concept, or plan, that organizes the image. Nature is full of natural patterns.
PROPORTION refers to relationships of size and form between the whole and it's parts. Although proportion can often be mathematically measured and described, it can also be compared to one's expectations of natural or ideal form. Proportion is usually related to size and scale. Proportion often influences the emphasis of an image, and our sense of space.
Composition reflects intention. By knowing and applying or choosing to break these PRINCIPLES OF COMPOSITION you can capture better images. While a lot of thing can be easily corrected in today's digital world in post production, composition generally cannot. Outside of cropping, you are stuck with what you captured when you snapped the shutter. Good compositions can be manipulated to become better and bad compositions will never improve to a point of becoming good.