Outside of large format cameras, film cameras come in two basic
types: those with through-the-lens viewing and those with separate
viewfinders. Digital cameras offer some variations on those themes.
Some entry-level digicams only have optical viewfinders. Just like a
disposable camera, you look through a window close to the lens. Once we
go beyond entry-level, most digicams have some type of LCD that not
only lets you review the pictures you've taken, but can also be used to
compose your image using the same imager that will take the
photograph.
A step beyond this brings us to digicams that only provide
through-the-lens viewing. This may mean the camera only has an LCD for
composing and viewing images, dispensing with the optical viewfinder.
In some cases this means two electronic viewfinders, and with digital
SLRs, it means true optical through-the-lens (TTL) viewing like you'd
find on a film SLR (single lens reflex). Because electronic viewfinders
often exhibit a slight lag, a digital SLR will usually be more
responsive than a camera that depends on an LCD display. (Olympus has
created a digital SLR that includes an active LCD for viewing, the
first camera of its type.)
At the top are digital SLRs with a full-frame 24x36mm imager.
One type of digicam to watch out for is the popular LCD-only style.
These cameras have no optical viewfinder whatsoever, and because LCDs
tend to wash out in bright light and glossy screens reflect a lot of
light, they can be nearly useless outdoors. They can also be
conspicuous in low light situations, since you can't turn off the
display and take pictures with them. I tried to steer my customers away
from these, and my own choice in a compact point-and-shoot digicam was
the discontinued Konica-Minolta
Dimage X50, the last of that line to include an optical
viewfinder.
Optical Viewfinder Only
LCD viewfinders have a slight delay between what's happening in the
real world and what you see on the digicam's display. The delay (or
lag) used to be quite noticable, but it has improved significantly in
recent years to the point where most users of recent digicams don't
notice it at all. An optical viewfinder works in real time (no delay)
and tends to offer a bright image with no tendency to wash out in
bright sunshine. It's also very inexpensive compared with electronic
viewfinders and reflex (SLR) viewing. Those are the good points.
On the down side, viewfinder quality ranges from excellent to poor,
and eyeglass wearers should be sure to test how well a viewfinder works
with your glasses on before investing in a digicam. Worse yet, a
camera without an electronic display gives you no way to view your
pictures in the field to make sure you "got it". Fortunately LCDs have
become so inexpensive that almost all digicams today have them.
Digicams that only have optical viewfinders are only recommended for
those on a tight budget or looking for a very inexpensive camera to use
in a risky setting (at the beach, canoeing, etc.).
Display Size and Resolution
In the early days of digicams, 1.6" to 1.8" LCD displays were
common, but nowadays it's easy to find digicams with 2.5" to 3.5"
screens. Another improvement has been usability in bright sunlight,
which used to be a real problem area. Look for screens that are bright
and have an anti-reflection coating, as bright light can wash out some
LCDs and reflections can make some hard to use in bright
situations.
Just as computer displays come in different resolutions, so do
digicam displays. However, there's a hugs difference in scale. A
typical laptop computer might have a 1024x768 or 1280x800 display, up
from 640x480 and 800x600 8-10 years ago. Those numbers translate into
roughly 0.75 MP, 1 MP, 0.3 MP, and 0.5 MP respectively. By comparison,
it's not uncommon for a low cost digicam to have a 115,000 pixel (0.115
MP) display (maybe 400 x 288 pixels). Better digicams may have a
230,000 pixel (0.23 MP) display (about 576 x 400). Very few digicams
offer even a 640 x 480 display, which was the norm for computer screens
as far back as 1987.
What this means is that you can't use the LCD screen to determine
that your photo is really sharp, as even the better 230,000 pixel
displays have 1/20 the quality of a 5 MP digicam image. You can still
tell when a photo is blurry, but you can't tell just how sharp it is
without zooming in (which means looking at just the tiniest bit of your
image on your digicam's screen) or taking a good look once the file is
on your computer.
Optical Viewfinder Plus LCD
Until big LCDs (over 2") became affordable and could work well in
sunlight, the most popular type of digicam had an optical viewfinder
for composing pictures and an LCD for reviewing photos and
through-the-lens composition. The LCD tends to be the most battery
hungry part of the camera, so using the viewfinder when shooting can
help your batteries last longer.
Basic cameras of this type have an LCD on the back. More
sophisticated models may allow the lens or LCD to swivel, allowing some
very creative angles.
These cameras tend to be versatile and modestly priced.
LCD Point-and-Shoot
This category has come into its own in recent years, displacing the
models with both optical and LCD viewfinders at most price levels.
Since most digicams have an LCD anyhow, eliminating the optical
viewfinder reduces the size and cost of the camera. When buying a
camera of this type, be sure the LCD can be used in bright sunlight, a
real problem area with older digicams and some of today's cheaper
ones.
Electronic TTL Viewing
This class of digicams doesn't have an optical viewfinder. It may
look similar to a 35mm SLR, but the "prism" viewfinder is really an
LCD. The Minolta Dimage 7i, Fujifilm FinePix S602, and Nikon CoolPix
5700 are examples of this type of camera (in 2002 when this article was
first published).
Because you're viewing via the camera's digital imager, framing can
be very precise. However, you may notice a lag between an action in the
real world and the image you're viewing, especially on older digicams.
Also, some photographers find it distracting - too much like watching
television - to use a non-optical reflex-type viewfinder.
That said, this is a less expensive way to build a digital camera
that relies on TTL viewing compared to true SLR viewing.
Optical Reflex Viewing
Here we move to cameras very much like the 35mm ZLR and SLR cameras.
You can interchange lenses from the Nikon, Canon, Sony/Minolta Maxxum,
Pentax, Contax, etc. system.
All of these models work like a 35mm SLR, flipping up a mirror and
blanking out the viewfinder briefly when the picture is taken. Olympus
uses a beam splitter to avoid this on some models, sending some light
to go to the viewfinder while the rest passes to the imager.
Digital SLRs are the most flexible, most responsive, and most
expensive category of digicams, and they are the best suited for sports
photography, as they focus quickly and respond to the shutter button
almost instantly.
Conclusion
There is no right and wrong here, just a lot of different options.
What's right for you will depend on your budget and your needs,
although serious photographers - espcially those used to 35mm SLRs -
are likely to gravitate toward models that handle like SLRs.
Next: Lenses
