Shutter Speed
Zooming in on a subject not only magnifies the subject, it
also magnifies camera shake. The rule of thumb is that your
shutter speed should be faster than the 35-mm equivalent
focal length of the lens. The widest lens setting on most
P&S cameras is about 35 mm, and most zoom in to at
least 120 mm. Hence, you want your shutter speed to be 1/30
s or faster for the wide angle shot or 1/125 s or faster
for the telephoto shot to capture a sharp image. Any
slower, and you'll most likely get a blurry photo.
Many cameras now have some sort of built-in mechanical
stabilization that can compensate for this shake (digital
image stabilization doesn't count—it simply raises the
ISO). You can expect to beat these shutter speeds by a
factor of four (two stops), so 1/30 s becomes 1/8 s and
1/125 s becomes 1/30 s.
Flash
The on-camera flash is counterintuitive. It's very useful
for filling in harsh shadows in bright sunshine. It's not
useful for lighting up dark scenes.
Our eyes can capture a much wider range of brightness
levels than a camera or printer. Suppose it's noon, and a
friend is standing in the shade with a sunlit landscape in
the background. You can see the detail in your friend's
face, but your camera will register him/her as a black
silhouette with a properly exposed landscape in the
background. In this case, turn on the flash and fire away.
Your P&S camera will balance the exposure and capture
both the landscape and your friend. Look through the manual
for a fill-flash setting—this is what you want in these
situations.
As for lighting up dark scenes, the light from a P&S
camera's flash falls off very quickly (1/r^2 for you geeks)
and dies out after a few meters. It’s not going to light up
the Eiffel Tower. Hence, if the flash is the primary source
of light, subjects close to the camera will be washed out
and your background will be black. Furthermore, the flash
on a P&S camera is mounted right next to the lens,
which means that the lens does not capture the shadows cast
by the flash. You're left with a flat, two-dimensional
image where your subjects will look like a deer in the
headlights. Not using the flash in these situations will
often result in a shutter speed longer than the guidelines
mentioned previously. To compensate for the lack of light,
brace yourself against something solid while taking the
picture, crank up the ISO, or put the camera on something
stable and use the self timer. You may need to put your
camera in its night mode once it gets past twilight to
ensure that the shutter stays open long enough.
ISO
ISO measures the camera's sensitivity to light. The higher
the ISO, the shorter the shutter speed needed to make a
given photo. A photo that requires 1/15 s at ISO 100 only
requires 1/60 s at ISO 400. The tradeoff is that increasing
the ISO also increases noise in the image. P&S cameras,
with the exception of some Fujis, look rather grim by ISO
400, and even small prints may look objectionable at ISO
800.
Camera Support and Self Timer
As the light dims, another option is to rest the camera on
something solid and use the self timer to trigger the
shutter. Something solid could be a pocket-sized tripod,
the travel photographer's secret weapon, or a table with a
pebble under the front of the camera to orient it slightly
upward. Whatever the case, always use the self timer to
trigger the camera when it's supported. Most cameras have
both a short delay setting (perhaps 2 s) if you don't want
to be in the picture and a longer one (perhaps 10 s) if you
do.
Turn off the camera's image stabilization function and drop
the ISO to the lowest setting when using it on a support to
get the sharpest image.
Pre-Focus
P&S cameras tend to focus on whatever is in the center
of the frame, like the horizon between the heads of the two
friends you're photographing. In that case, center one
friend in the viewfinder, hold the shutter release halfway
down, recompose the image, and then push it all the way
down. If it's quiet, you'll likely hear the lens focus
during the half press.
Make Lots of Pictures
Unlike film, there's no cost associated with a bad picture
other than a second or two to delete it. Don't blast away
mindlessly, but don't be afraid to make multiple pictures
of the same subject. This is doubly true when photographing
people, as it can take a dozen tries for the subject's
expression to come together. A burst mode setting is
particularly handy in these situations.
Sidebar: Megapixel Madness
Camera manufacturers have successfully convinced a gullible
public that the quality of a camera has something to do
with the megapixel count of its its sensor—a ten megapixel
camera must be twice as good as one with five megapixels.
The fact is that contrast, color, and tonal reproduction
are equally important in perceived image quality, and that
all of these qualities suffer as the megapixel count
increases. However, they can't be quoted as a number and
therefore have zero marketing value.
Packing in more pixels also increases noise in the image.
We're now seeing cameras with obvious noise reduction
artifacts at their lowest ISO setting. What's the point of
all those megapixels if the image processing pipeline
smoothes them together to control noise?
Here's a great example. The
images on the left come from the Fuji F50fd, which has 12 megapixels. The
ones on the right come from its predecessor, the
F31fd, which has 6 megapixels. The
images from the 6 megapixel camera look a lot better
to my eyes. There's also a great editorial on Adorama's web site from
early 2007 about this nonsense, and David Pogue wrote
about it here and here.
How many megapixels do you need? I can't answer that for
you, but I've made beautiful 16"x20" prints from my 6
megapixel Fuji F30.
Which current P&S models are worth considering? Most of
them pretty much suck once you move off the base ISO. The
Panasonic LX–3 and Canon S90 both look like steps in the
right direction.
Last edit: 21 December 2009
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