7

CHAPTER
NIGHT AND LOW-LIGHT PHOTOGRAPHY / The Nighttime Sky

problem becomes how to get 14,400 images on a

single memory card without running out of

power. Here are some solutions:

    ■   Big memory cards. Memory card sizes seem to

go up every year, with Compact Flash cards

now in the 32GB range and SD cards reach-

ing 128GB, which is a lot of space, especially

for the smaller JPEG files mentioned in the

previous section. Some cameras also have two

card slots and allow you to shoot until one is

full, and then start to fill the second card.

Another option is to use a product such as the

Eye-Fi, which wirelessly transmits the images

to a nearby computer, allowing you to take an

unlimited number of photos.

    ■   Tethered shooting. You can attach your cam-

era to a computer and allow the computer to

store the image files automatically as you take

them. This solution is great when you are

close to home or where there is a source of

power, but not so great on location, as you

now have to keep the laptop and the com-

puter running off a separate power source.

    ■   Power cords. A fully charged battery might

last the full time needed, but if you can plug

your camera into a power source, that might

be a better idea. For example, the Nikon

EH5a Adaptor allows you to plug the Nikon

D700 into an outlet so that you don’t have to

worry about running out of battery power.

Before you go and purchase any of these items,

make a small test movie to see if this is actually

something you want to take further. Just follow

these steps:

1. Pick a scene.


2. Do the math.


3. Program the remote.


4. Set up the tripod and camera.

Working out the math

I am sorry to say that this part has math, but the
good news is that the math is actually pretty easy.
The key to the math is to know how video works.
Most film movie clips are usually around 24
frames per second (digital footage is usually 29.9
frames a second so if you want that, work the
math out with 29.9 instead of 24), so if you work
with that number as a basis, you will need 720
frames for a 30-second video clip, 1,440 frames
for a minute, or 43,200 frames for a 30-minute
movie. The next step is to take the length of the
event and divide it by the number of frames
needed to get the interval between the images.
So, for example, if you want to capture the sun
setting over a 30-minute period of time and
create a 30-second movie, then you will need to
take 720 individual images during 1,800 seconds
of the event.

The basic equation is:

Length of event in seconds / length of movie in
frames = interval between frames

So, in this example, 1,800 seconds (length of the
event) divided by 720 frames (length of the
movie) equals an interval of 2.5 seconds between
photographs.

If you want to shoot a 4-hour time lapse of the
night sky and create a 10-minute movie, then
you take 4 hours (or 240 minutes multiplied by
60) to get 14,400 seconds as the length of the
event. Then you divide that by the 14,400
frames (10 minutes or 600 seconds multiplied by
24 frames equals 14,400 frames), which creates a
10-minute movie with 1 frame for every second:

14,400 seconds / 14,400 frames = 1-second inter-
vals between frames

That works out really nicely, except that you
need to take 14,400 individual frames to create
the movie at 24 frames per second. So the