Shutter Speeds
Many of today's SLR cameras offer action-stopping shutter speeds of
1/2000 sec. or faster. None of the point-and-shoot models come close,
although some do offer speeds fast enough to stop most action.
Looking through the list of zoom models in Popular Photography, the
top shutter speed ranges from 1/250 to 1/770 sec. 1/250 is enough to
stop for most human action, but even 1/770 isn't enough to stop
an Indy car. That said, if you plan on shooting car races - or even
bicycle races - look for a model with 1/500 or faster. You'll also tend
to get better action stopping shots of soccer and football at
1/500.
Shutter speed interplays with focal length due to camera shake. As a
general rule, you can handhold a picture at 1/F (where F is the focal
length of your lens) and not worry about camera shake. The longer your
lens, the higher the shutter speed you need to use to avoid camera
shake - this can become a big factor when shooting something as long as
the Pentax IQ Zoom 200 at the long (200mm) end.
Film Speed, Part 1
The third part of the equation is film speed. To get a higher
shutter speed, shoot faster film.
A ancient rule of thumb is that on a sunny day, correct exposure
will be f/16 at 1/S, where S is the ISO rating of your film. That
really comes into play with today's point-and-shoot zooms, especially
at the long end.
Again, let's look at the Pentax IQ Zoom 200 at the long end, which
is f/13. With ISO 100 film on a clear day, we're looking at a top
shutter speed of about 1/150 sec - low enough that camera shake may
well be a problem, as well as subject movement in sports like soccer
and football. If we switch to ISO 200 film, we move the shutter speed
to a much safer 1/300 sec. Moving to ISO 400, we'll be shooting at the
camera's highest shutter speed of 1/400 and an f/16 aperture. This
makes ISO 400 film ideal for shooting sports on a sunny day with this
camera.
But on a hazy or overcast day, we can easily lose two stops or more
of light, which means the ISO 400 film is now shooting 1/150, and the
problem of camera shake returns. Moving to ISO 800 bumps us to an
action stopping, shake reducing 1/300 - which helps explain why many
camera shops now recommend 800 speed as the best all around film for
point-and-shoot cameras with longer lenses. (Fujifilm's 800 speed film
is excellent.)
Flash
You really don't want to know the sad realities of flash on zoom
lens point-and-shoot cameras, but you need to.
First, the built in flash is pathetically small and underpowered.
Why? To keep the size, weight, cost, and battery drain down. A bigger,
more powerful flash would increase cost and size, which makes it harder
to market the camera.
As helpful as Popular Photography's annual point-and-shoot
roundup is, even they don't publish flash range information in their
summary, although they do a great job of mentioning it when they review
individual cameras.
For instance, the May 2002 issue reviewed the Fujifilm Zoom Date
1000 and Yashica Zoomate 110W. At the 28mm setting, the Fuji is rated
to 9.5' with ISO 100 film and the Yashica to 10'. Multiplying distance
by aperture, the Zoom Date 1000 has a guide number (GN) of 55 (9.5 x
5.8) and the Zoomate a GN of 60. That's actually a full stop more power
than the built-in flash of most 35mm SLRs, but the SLRs tend to have
higher speed lenses and thus don't need as much power.
All things being equal, we would expect that as the Fuji zooms for
100mm and f/10.5, the maximum flash range would drop to 5.2' with 100
speed film. Likewise, the Yashica at 110mm f/13.1 would only reach 4.6'
at ISO 100.
Fortunately, all things are not equal. To help offset the reduced
light transmission as the lens zooms, the flash also zooms. In the case
of the Fuji, the flash is rated to 6.5' at the long end, giving us a
guide number of 68 (6.5 x 10.5) - a small but helpful boost from 55 at
the short end. Likewise, the Yashica flash is good to 6' at 110mm,
which gives us an impressive GN of 79. Of course, if you're using the
lens zoomed to the long end, you're probably shooting something more
than 7' away....
Zooming flash helps, but only so far. I every case, a zoom
point-and-shoot has a much greater flash range when the lens is as the
short end. As you zoom in to capture the kids in their school play, you
actually reduce the likelihood of having an acceptable exposure. You
are far better off moving closer to the stage to take your flash
photos.
Film Speed, Part 2
Faster film comes to the rescue again. Because light falls of with
the square of the distance (the same kind of ratio we saw with
f-stops), doubling your film speed increases your flash range by 40%.
Here's how that works out with the two cameras mentioned above:
|
ISO 100 |
ISO 200 |
ISO 400 |
ISO 800 |
1600 |
| Fuji 28/5.8 |
9.5' |
13.4' |
19' |
26.8' |
38' |
| Fuji 100/10.5 |
6.5' |
9.2' |
13' |
18.4' |
26' |
| Yashica 28/6 |
10' |
14' |
20' |
28' |
40' |
| Yashica 110/13.1 |
6' |
8.5' |
12' |
17' |
24' |
It's very easy to be 10' or more from your subject when shooting
indoors, so you want to avoid ISO 100 film for flash photography with
this type of camera. In fact, I'd suggest nothing slower than 400 speed
so you can zoom in on your subject from 12-13' away (and no
further).
And just as we saw with the Pentax IQ Zoom 200 outdoors, moving to
800 speed film gives you that extra edge with flash as well - but you
still want to be less than 20' away from the stage when shooting that
school program.
This is just one more reason camera store employees generally
recommend ISO 400 or 800 film for zoom point-and-shoot cameras. (And a
lot of us shoot the same thing in our SLRs for exactly the same
reasons.)
Autofocus
Underexposed flash pictures are probably the most common problem
with this type of camera, and using a fast enough film can really help
there. But the second biggest problem has nothing to do with film -
it's a matter of focus.
Until about 2002, autofocus point-and-shoots were consistent in
always and only focusing on the center of the picture. That was great
if that was where your subject was, but what happened when you were
shooting two people with some space between them? That's right, the
camera focused on the background, which would be tack sharp with two
out-of-focus people in the foreground.
Unless you're using one a camera that actually analyzes your
composition and makes an educated guess where you want to focus (not
that common in film point-and-shoot cameras), you need to remember that
these cameras focus in the center of the frame. If your subject is
going to be off center, you need to make sure the camera you buy lets
you focus on your subject, lock focus, recompose, and then take the
shot - and learn how to use this feature as soon as you get the
camera.
