Your brain might forget that a
television picture is really a series
of scan lines moving faster than the eye can detect. But the camera
isn't fooled so easily, and often, first attempts at
capturing TV images result in mysterious black bars spanning the
screen, as shown in .
Figure 1. Television picture caught in mid scan
If you have a digital SLR or an advanced prosumer camera that has a
Shutter Priority setting, all you have to do is set the shutter speed
to 1/15 of a second to solve the problem. That exposure is long
enough for the television to complete a full scan cycle and render a
complete picture, as shown in .
Figure 2. A complete picture of the television screen
But what if you don't have a
Shutter Priority mode or some other
way to set the shutter speed? Does that mean you're
banned from television photography? Certainly
not. You just have to get a little creative. Your success depends on
fooling the camera into using a slow shutter speed. Here are a few
tricks to accomplish this:
-
Set the ISO to the lowest setting, usually 50 or 100. This helps
create a longer exposure, which is what you want.
-
Turn off the flash. It can't help you in any way
with this type of photography.
-
Turn on the Spot Meter function, if your
camera has one. That way, the camera will meter off the TV screen
only and not be affected by ambient room light.
-
Mount the camera on a tripod to steady it during the exposure. The
longer shutter speeds are good for preventing scan lines from the
television, but they put you at risk for camera shake, which
deteriorates sharpness.
-
Try to time the exposure for when there isn't a lot
of movement on the screen.
-
Shoot multiple exposures. The nice thing about using a digital camera
is that you don't have to worry about wasting film.
These techniques will usually render a good image of the TV screen.
But
if for some reason you're still getting scan lines,
there are a few super-tricks you can try. If your camera has a
Nighttime Mode or a Long Shutter mode, activate it. Also, get your
best pair of sunglasses—neutral in color, if possible—and
hold them in front of the lens. They will serve as a polarizing
filter and darken the image, forcing the shutter to slow down.
TIP
Sometimes, digicam autofocus systems have a hard time focusing on
television screens. Hold the shutter button halfway down until you
hear the focus-confirmation beep. Then, continue pushing down to make
the exposure.
TV pictures have that certain, well, television
look. But for those times when you want to document a
world that would otherwise be out of reach, these techniques will get
the job done.