Understanding Depth of Field

Budding movie makers and film students will find they are bombarded with terms and phrases that are said to be vital to the cause, but one that is undeniably essential is depth of field, so let’s have a look at what it is, why it is important and how you can use it to your advantage.

Depth of Field Explained
Put simply, depth of field is the length of the focus of your shot; to explain that a little more, a shallow depth of field will concentrate on the foreground much more than a deeper one. It is all about the focal length that you choose to use, and for those using modern day video cameras there is much to consider.

Depth of Field can be used to enhance your subject.

The underlying preference among movie makers – professional and otherwise – is that a shallow depth of field gives a better result. The reasons for this are easily explained: unless you have a specific reason to focus on something in the background you want the action in the foreground to be the point of interest. Too sharp a background can draw attention away from the point of the shot.

Of course, there are always experiments waiting to happen and depth of field is an area in which movie makers can experiment to a great degree. So how do you vary the depth of field?

Techniques and tips
The first thing we have to discuss is how to vary the depth of field, and while this is simple to do when mastered, it takes practice and experimentation to achieve to the right degree. You should consider the equipment you are using; a high end professional camera will be a more complex beast, but the standard digital camera you are likely to be using should be in manual focus mode. Not only does this give you better control of the focal length, but it allows you to try different approaches in varying depth of field.

Another point to remember is that the distance between the subject and the camera also has an effect: one tip is to move the subject closer to the camera for a shallower depth of field. Contrary to this, a shallow depth of field can also be achieved by moving back from the subject and using the zoom function. Try both and see the difference in the results.

It is also a point to remember that many cameras will achieve a shallow depth of field to greater effect when used in portrait mode, another experimental method that you should try. Filters can also help to achieve the right effect – especially natural density filters. These filters are designed to limit the light that enters the lens, and thus allow the user to widen the aperture. This can provide an impressive effect where depth of field is concerned.

To summarise, depth of field is a subject that, once understood, can have a profound effect on the results of your filming. We have talked mainly about shallow depth of field, but it is also worth experimenting with a deeper focal length for different results.