A shallow depth of field is an in camera technique most commonly associated with photography, although it also relates to video production. So what is depth of field and how is it achieved? What situations should it be used in, and of course when shouldn’t you use it.
What is a shallow depth of field?
A shallow depth of field is simply a restricted focus area within an image. For instance if you were filming a person talking to camera, that person would be in sharp focus, with both the foreground and background blurred or less sharp. The image example above is taken from our Olive Grove video, Tim who presents to camera is isolated from the background drawing the audiences attention to him. This creates a far more professional and desirable image.
The ‘blurry’ area is sometimes referred to as bokeh.
How to achieve a shallow depth of field?
This look is only easily achievable on large sensor cameras, generally cameras that allow interchangeable lenses, such as DSLR photography cameras, and large sensor video cameras such as the canon C300 (or any of the high end production/ cinema cameras). DSLR cameras became popular as they are the most affordable tool to achieve this look, whilst still producing high image quality.
To achieve a shallow depth of field you must set your lens to the widest aperture. An aperture is the hole within the lens that opens to allow light to hit the sensor, ultimately recording an image. A wide aperture is depicted by a low value F-stop number, for example F2.8, F1.8, F1.4 etc. The smaller the number the wider the aperture (think opposites….or the lower the number the smaller the focus area). Using a small aperture such as F22 would give the opposite effect, making the whole image sharper from front to back.
Note cheaper lenses may not offer an aperture wider than F3.5 upwards! The most desirable lenses are F2.8 or lower.
How to achieve a shallow depth of field on a camcorder or DV camera?
Older cameras, fixed lens cameras or those with a smaller sensor will always struggle to create a shallow depth of field. However if this is a look you require the best way to do this is to get as far away from your subject as possible, then zoom in to fill the frame. A camera at full zoom will always create a ‘shallower’ depth of field. However this is not a practical way to shoot, and the visual results will not be any where near identical. If this is a look you require often, invest in the right tools for the job.
When using a shallow depth of field can get tricky.
Walking and talking shots
Groups of multiple people
Times where the background is key to the story.
You will learn when to dial down your settings in order to make shooting practical. Pulling focus whilst filming is an art, and in many cases can require more than one person.