Size and Composition in Close-Up Photography
To use size as a compositional element in close-up and macro photography, you first need to figure out what you want to say about your subject. You can use a size relationship between two objects to clue viewers in on how big your subject is, or create a sense of depth by having one object appear much larger than another in the frame.
50mm, 1/15, f/16, 400
If your subject is commonly known (such as a penny), then your viewers already have an idea of its size without any extra information. If not, you may have to include something known (like that penny again) in your frame to give viewers an idea of the size of your subject.
If you include two objects in your frame that viewers know to have the same or a similar size, you can use their size representations in the frame to show distance, or depth. When the two appear to be similar sizes, viewers know that they are very close to one another. When they appear to be two very different sizes, viewers know that there is distance between the two.
When working with a single subject and no supporting elements to use for scale, you can control how large the subject appears by how much space you grant it in your frame. Leaving your subject very small in the frame and surrounding it with a lot of space gives viewers the sense that the subject is less significant or less dominant.
By showing your subject largely in the frame and minimizing the space around it, you cause it to appear significant, or dominant. This photograph shows one subject presented in a significant sense and an insignificant sense.
100mm, 1/160, f/8, 500 100mm, 1/160, f/8, 500
In the first image, you can tell that this scene is about the connection, or the bond between the two chain links. The second shot makes the message appear to be more about the chain as a whole, and less about that one specific connection.