Despite all the advances in technology, the pictures that we shoot today are as flat as the ones that were taken by the Victorian pioneers of photography. We still take pictures of a three-dimensional world—and, with few exceptions, turn them into two-dimensional representations.

Whether you look at the picture on a computer monitor, on your camera’s LCD display, or printed out on sheet of high-gloss, premium photographic paper, the image is flat; it has no physical depth.

For this reason, creating an illusion of depth is all- important in photography. We frequently want to add the missing third dimension—to make our pictures more representative of the subject matter itself.

There are numerous ways in which you can do this. The human visual system uses two eyes to provide a stereoscopic view of the world, helping us to judge distance. However, many of the clues about depth that we use subconsciously when we look at the real world come from the content of the image itself. By learning to include as many of these clues as possible, photographers can create a better three-dimensional experience in their pictures. Many of these telltale signs will be there in the composition anyway—but making the most of them will make your images come alive.

Some of the tricks have been covered already, such as using lighting and tone to reveal three-dimensional form, or including dominant and recessive colors. But there are many other techniques for creating a sense of distance. 

Perspective is one of the most important properties that you can manipulate in order to create a stronger feeling of depth. Perspective is, actually, a series of different tricks that are used by the human brain to judge distance—to work out which objects are closer, and which are farther away.

It is linear perspective that obsesses the art student, because it is necessary to draw parallel lines so that they converge convincingly on the paper. As a photographer, you have no such problems—the lens and imaging chip do everything for you. However, the feeling of linear perspective can be accentuated through viewpoint and the choice of lens setting; it can also be purposely reduced, to make objects look much closer together than they really are.

Other forms of perspective that can be used to a photographer’s advantage are: diminishing size (things look smaller the farther they are away); overlapping forms (from certain viewpoints, closer objects obscure more distant objects); and aerial perspective (particles in the atmosphere make distant objects look less sharp). Additionally, depth of field and image composition can be used to control the feeling of distance in a picture.

Depth of filed

one of the main ways in which you can alter a picture using the camera controls alone is by changing the depth of field. Focus on a single point in the scene, and there will always be areas closer and farther away that are also sharp. This zone, where things are in focus, is known as the depth of field. Its extent can vary significantly.

The simplest way to control the depth of field is by varying the aperture—the opening in the lens that is also used to regulate exposure. The size of the aperture is measured as an f-number. A small aperture and large f-number gives a greater depth field. A large aperture and small f-number reduces the depth of field,  and can be used to throw areas out of focus. The depth of field is also dependent on  other factors—notably the focal length of the lens, and the distance between the camera and the point that the lens is focused on. With a long zoom setting and the subject close to the camera, there is less depth of field to play with. 

Depth of field is frequently restricted to hide distracting backgrounds. This portrait emphasizes the aging features of this Chinese gentleman—but in order to do this, the busy street behind needed to be softened. By using a short telephoto lens close to the subject, and using the largest aperture available with the zoom, the shops and people in the background become a blur. 

Focus effect  / Depth of field

Our brains understand that some posts are farther away because they are slightly out of focus. Known as depth of field, this is a useful tool for providing
a three-dimensional effect.

In architectural and landscape photography, you typically want as much of the scene to be sharp as possible. A wide-angle lens and small aperture are the simple solution, as used here. 

EXTREME MEASURES Super-wide-angle lenses offer great depth of field but, as in this image, they may cause distortion. It is hard to exercise any control using aperture or distance—use these lenses when you want everything to be sharp. 

Leading Lines

From the right camera angle, the horizontal lines of a building can be made to look as though they converge. This effect can be exaggerated by changing camera positions and by using a wider lens setting.