Motion in still photography
There are two primary ways of recording motion or suggesting motion in still
photography.
1.
Use a shutter speed slow enough to record the blur of something that is
moving.
2.
Use a shutter speed fast enough to freeze the action of something that
the viewer will understand, from context, must have been moving.
The following two slides freeze moderately fast action
through the use of relatively fast shutter speeds.
Note that there are actually several factors that combine to
determine whether a particular action, or object or person
in action, will record as blurry or sharp. These do include
the shutter speed, but they also include:
- the speed of the action or object or person in action
- the distance between the camera and the object in
action (The smaller the distance, the faster the shutter
speed needs to be to freeze the action.)
- the angle of view of the camera in relation to whatever is
moving (Objects moving perpendicular to the lens of the
axis do not exhibit as much relative motion as those
moving across the field of view of the lens, and will not
record with as much blur, if all other factors are equal.)
The next image shows water in motion. Note that the motion
is swirling: no matter what the angle of the camera in relation
to the water, there’s really no way to minimize relative motion,
since there’s motion in a number of different directions.
Here, the shutter speed used was slow enough for the motion
of the water to record in somewhat blurred fashion. Note that
this technique of using a fairly slow shutter speed (let’s say,
1/125th or 1/60th of a second) to let motion blur will work
when you’re close to something that is moving very quickly,
as is the case in these two shots of the river. But if your
subject is moving too slowly, you’ll have to use such a slow
shutter speed in order to record the motion as a blur that you
will run the risk of blur caused by camera motion (that is, the
camera moving in your hands during the exposure) -- unless
you brace the camera, as on a tripod.
The next two slides, of a dance class, show dance students
holding positions. (At least, that’s what it looks like to me:
these are student photos, as are most of the others in this
presentation.) They are not actually moving. However, their
positions, which are inherently somewhat unstable, and which
can be held only with some skill and effort, suggest potential
movement. Because we can relate to these poses simply by
virtue of our own experience of what various positions feel like,
we “read” movement, or potential movement, into these shots.
In addition, the second of these two photographs also conveys
a sense of movement through the overlapping of several legs
of several students, each in a slightly different position -- as if
showing one leg moving through space over time.
I took the next three photos, strictly for purposes of
demonstration. What you will probably notice first, beyond the
fact that all three photos are composed identically, is that
there is a change from very little depth of field to a lot of depth
of field. You’ll need to look much more carefully to see the
change in the way the second hand of the small alarm clock is
recorded. In the third shot, this second hand is blurred
through an arc of roughly four seconds, which was the
exposure time of this shot. Such a long exposure time was
necessary in order to allow for the f-stop to be stopped down
fully, and it was this very slow shutter speed that allowed for
the slow motion of the second hand to record as a significant
blur.
The next three photographs were created by a former photo
student working independently on a long term project all about
motion. She used a combination of ambient light and the flash
built into her digital camera for these shots. By using a slow
shutter speed (long exposure) in combination with a very brief
flash, one can achieve an interesting mixture of sharpness and
blur. Because the flash only reaches objects fairly close to the
camera, these close objects are generally the only ones that
record from the flash exposure. Objects and other elements
further away from the camera are recorded primarily with the
ambient light (that is, the light that is in the scene, apart from
the flash) over the length of the full exposure time. They are,
therefore, usually fairly blurry. This is true even when they are
not moving, simply because the camera is moving.