The best bet is to set the focus manually. The
easiest way to do this is to pick a spot and focus
using the built-in auto focus, and then, without
touching the lens focus ring, switch the focus to
manual.
The last setting is the most important and the
hardest to deal with: the exposure setting. The
exposure of a single image is easy, but how should
you decide what settings to use when the light
will change over the period of the time lapse?
This is easier when the light change is minimal,
but a situation like a sunset takes a little more
guesswork. To make things clear, I did not want
the exposure to adjust for the changing light con-
ditions as that would not look natural, but instead
I wanted the scene to change from light to dark.
The question is, how much lighter than a proper
exposure do I start at and how much darker than
a proper exposure do I end at? I set the camera to
manual and set the shutter speed and aperture to
overexpose the scene by a full stop. When the
time-lapse was done, the camera was recording
the scene as underexposed by two stops. This
gave me a very nice movie that starts very bright
and slowly goes dark, as if you were at the actual
scene. As you can see in Figure 7-13, there is a
great difference between the first and last frames.more images on a single memory card, which is
important because of how many images you need
to take to make a movie. It’s a lot.
Looking at HD television, the highest resolution
of the screen is 1920 × 1080 pixels, which is not a
very big image file. With the Nikon D7000, for
example, the smallest JPEG file is 2464 × 1632,
which is still bigger than you need for HD televi-
sion. The Canon Rebel T3i allows you to pick a
resolution of 1920 × 1280, and even better, it has
a widescreen mode of 1920 × 1080.
Because you only need to use a small JPEG image,
you must set the white balance correctly before
taking the first image; this keeps the color consis-
tent for the whole movie. It is possible to use the
Adobe Photoshop Camera Raw module or the
Adobe Photoshop Lightroom Develop module to
adjust the white balance of JPEG files, but it
takes a lot of time and computing power, so if you
can avoid it, all the better.
The next step is to set the focus, and manual is a
good way to go, especially if there is a chance that
the focus could change during the exposure. For
example, as the image is being taken, a person
moving across the frame will cause the focus to
shift because the camera’s auto focus will shift
focus to any subject that is closer to the camera.
ABOUT THIS PHOTO The first and last frames of the time-lapse. All the frames in the movie have the same exposure; it is the fading light
that changes the look. 1/125 second, f/7.1, and ISO 500.
7-13