As an integral element to film and video, focusing
determines the sharpness of an object or image by adjusting the lens, providing
an acceptable visual perspective known as the depth of field. The art of focus lies in knowing what part of the frame
needs it most, and the avoidance of over-shooting. For example, interviews or
‘talking heads’ within television are an excellent example, with the eyes of
the given subject being an important point for the viewer’s
attention
to be drawn to. However, much of this will lose meaning if you don’t learn
the behaviour of your camera itself and the way it captures distance,
sharpness, movement and zoom in relation to the focal plane (the area in which
the eye or camera draws attention to). Without any of these elements, the image
within the frame will appear ‘flat’, with no sense of immersion or depth.
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| Depth of field: Notice how the subject is sharp, while the background is soft |
To avoid this, and to gain an understanding of how integral
focus can be to your shot, practice is a crucial element. For instance, even
with the most professional equipment, manual focus is a critical skill with any
level of video production. Here are a few ideas to experiment with and try out:
Pulling Focus:
Within the frame, attention is drawn towards the subject
with the sharpest focus. This attention can be changed through the use of focus
pulling. For instance, a foreground subject (such as a person) can move away
from the frame, with focus instantly thrown back to the background, containing
a second subject.
Differential
Focus:
By using a deliberately narrow depth of field, emphasis on a
principal subject can be increased. This is down to the contrast between the
sharp focus of the principal subject, and the heavily out of
focus background (and sometimes a foreground subject is used as well which is also out of focus).
Zoom lens and
focus:
Provided the back focus has been correctly adjusted, this is
designed to ensure the focal plane is maintained throughout its range. By
zooming in without manual focus, images can lose focus and become distorted.
By becoming familiar with these ideas, you can be more
artistic and manipulative about what you want the viewer’s attention to be
drawn to. As an important but often overlooked aspect to filming, these
techniques are most often mastered through practice and experimenting.
To find out more about the different techniques with focus,
check out these links:
