[Published:2006-03-20 09:05:06 Views: 985 URL: http://sellcamera.net/knowledge.php/1]
Introduction
Digital photography keeps getting better. Higher resolution, more
sophisticated controls, and better technology all make taking great pictures
easier than ever.
The Big Picture
From resolution to storage and from exposure control to white balance, we'll explain the digital camera terms you need to know.
The Specs Explained
Buying a digital camera isn't all about megapixels. We'll translate the jargon and tell you just how important each specification is to your purchase.
Digital Camera Shopping Tips
Before you head to the store, check out our advice for making a smart digital camera choice.
The Big Picture
Megapixels still matter a lot to digital camera shoppers,
in part because manufacturers and retailers hype that specification above all
others. If you're having a hard time figuring out which camera to buy, you may
be tempted to make a decision based solely on megapixel count; that's why nearly
all manufacturers print the number on the front of their cameras.
But a camera needs more than just a high pixel count to
take great pictures, so pay attention to other traits as well. For example, a
lethargic camera that takes too much time between shots may miss the best
action, and a big, heavy camera may spend more time on the shelf than in your
carry-on bag. A camera with no manual controls may take fabulous shots in bright
sunlight, but lousy ones in more challenging situations.
Key
Features
Resolution: If you intend to take pictures only to
e-mail them to distant friends or to print at snapshot size, a camera of most
any resolution will do. Even so, having more pixels gives you greater
flexibility--you can print sharper pictures at larger sizes, or crop and print
small sections of pictures. These days most cameras offer a resolution of at
least 4 megapixels, which is enough to make a sharp 11-by-17 print.
Size, weight, and design: To some users, how much a
camera weighs and whether it fits in a pocket may be more important factors than
resolution. PC World has tested cameras that weigh as much as 3.2 pounds
and as little as 4.1 ounces. Small cameras are convenient, but they frequently
have tiny dials and buttons that make changing settings somewhat trying.
Zoom lens: Inexpensive cameras often lack a powerful
optical zoom lens. If we had to choose between a camera with more optical zoom
and one with higher resolution, we'd take the model with the more powerful zoom
lens--it means you won't have to magnify your subject and then use software to
crop the image (and discard some of the resolution as a result). A few cameras
now offer zoom ratings of up to 10X. These lenses are great for nature or sports
photography, but you may need a steady hand or a tripod to avoid blurry pictures
at extreme telephoto lengths.
Be wary of advertised zoom ratings--many vendors combine
the optical zoom (which moves the lens to magnify the subject) with digital
zoom, which merely captures fewer pixels and magnifies those. Optical zoom gives
you all the benefit of the camera's maximum resolution, combined with the
ability to get closer to the action.
Manual focus: For close-ups or situations in which
the camera can't get a focus lock, switching to manual focusing can help you get
the shot. Low-end cameras often omit manual focusing or allow only stepped
focusing, which forces you to choose from a few preset distances.
Storage: At its highest resolution, a typical
4-megapixel camera can store eight to ten images on a 16MB "starter" memory
card. The size of the memory card a camera ships with isn't terribly important,
because you'll almost always have to buy another one (unless you're willing to
transfer your images after every handful of shots). CompactFlash, SD (Secure
Digital) Cards, and SmartMedia cards cost about $15 to $25 for 256MB, or $60 to
$80 for 1GB.
Batteries: Cameras use one or more of several types
of batteries: AAs, either nonrechargeable alkaline ($5 for four) or rechargeable
nickel metal hydride (NiMH, about $14 for four); high-capacity disposable CRV3s
(around $10 apiece, and some cameras take two); or proprietary rechargeable
batteries that can cost $35 to $75 to replace.
Movies and sound: Many cameras can capture video as
well as still shots, though typical-size memory cards don't hold much video
footage; the option is useful for taking short clips when you don't have a
camcorder.
Exposure settings: All digital cameras let you shoot
in fully automatic mode--just press the shutter release and you get a picture.
Most cameras also offer aperture- and shutter-priority modes, in which you
adjust the size of the lens opening or how long the shutter stays open, and the
camera automatically controls the other variable to give you the proper
exposure.
Typically, you'd use aperture priority to maintain control
over an image's depth of field--for example, to blur the background of a shot
while keeping the foreground sharp--and shutter-priority mode to capture
fast-moving subjects. A camera that relies exclusively on full auto would
attempt to keep both the foreground and background in focus in the former
example, and it would probably blur the moving subject in the latter.
Usually, cameras that offer priority modes also provide
full-manual exposure control, in which you set both variables. These modes make
a camera adaptable to almost any situation.
Menus: When evaluating a camera, consider how easily
you can reach common settings--resolution, macro mode, flash, and exposure
adjustments--and how easily you can play back just-taken images. Too many
buttons, and you waste time trying to figure out which button does what; too
many menus, and you waste time digging through them.
Scene modes: Some cameras try to entice prospective
buyers, particularly beginning photographers, with a large number of scene
modes--presets that are designed for a variety of settings and subjects, such as
the beach, fireworks, and underwater. However, selecting one of these less
common modes usually requires a trip to the menus, and multiple button presses.
Some cameras let you assign one of the modes--or a custom mode of your
creation--to a position on the control dial, where you can more easily access
it. Some single-lens reflex (SLR) cameras offer multiple positions on their
control dial for storing customized settings.
White balance: Almost all digital cameras allow you
to choose a white-balance setting via presets. This setting tells the camera
which elements in a shot should look white, and then by inference which elements
should look black and what everything in between should look like. If you're
finicky about color accuracy, look for a manual calibrator in which you press a
button while aiming at a white object.
LCD and viewfinder: Almost all digital cameras have
an LCD screen; these vary in size from 1.8 to 2.5 inches. The smaller size
limits your ability to review just-taken images on the camera. A good LCD is
essential for knowing whether you got the shot you wanted, and can usually give
you an indication of whether it was properly exposed. LCD quality varies widely:
Many wash out in sunlight or become grainy in low light, or the image may change
if you tilt the camera slightly. If you can, try a camera outside before you buy
it. Some cameras also have a viewfinder, which is a convenient backup for
framing your shots (and if you turn off the LCD when not using it, you'll save
battery power).
| The Specs Explained
A digital camera's megapixel count is an important
spec--but it is by no means the only one. Start with pixels, but make sure to
check a few other important numbers when considering a purchase.
A camera's megapixel rating is another way of expressing
its resolution. The higher the megapixel number, the higher the resolution. In
general, higher-resolution cameras let you produce larger, higher-quality
prints. Even a 3-megapixel camera (which is rare these days) can produce images
of about 2048 by 1536 pixels, allowing for crisp 8-by-10 prints. The trade-off
is that higher-resolution images take up more space on your camera's memory
card, so you may be able to take only a small number of shots before you have to
download them to your computer. The solution, of course, is to purchase a
larger-capacity memory card.
So if you're interested in producing mostly small snapshots
or images to send via e-mail or post on the Web, you probably don't need
anything better than a 3-megapixel camera. If you want to create large copies of
your masterworks, you'll want a camera that captures 4 megapixels or more.
| Feature |
Point-and-Shoot ($280-$600) |
Advanced ($400-$1000) |
SLR ($800 and up) |
| Battery life |
160 to 500 shots |
280 to 500 or more shots |
More than 500 shots |
| An important consideration.
Digital cameras quickly drain batteries--especially alkaline
batteries--which can be expensive and annoying. Battery life and cost often
aren't related; some cheap cameras have great battery life, and some expensive
ones use up a charge quickly. Either way, it's a good idea to buy spare
batteries. |
| Megapixels (resolution) |
4 to 8 megapixels |
5 to 10 megapixels |
6 to 13 megapixels or more |
| Somewhat important. This figure
provides a measure of how much fine detail a camera can capture. With more
megapixels, you can print larger photos with better image quality. But most
current models offer at least 4 megapixels, which is enough to make a sharp
11-by-17-inch print. |
| Exposure controls |
Some models offer aperture and shutter
priority, as well as manual control |
Aperture priority, shutter priority, and full
manual control |
Aperture priority, shutter priority, and full
manual control |
| Somewhat important. Scene modes
automate exposure settings, while aperture and shutter priority mode allow you
to customize the lens opening and shutter speed, respectively. Serious
photographers will value these controls, as well as full manual
control. |
| Focal range |
3X to 12X optical zoom |
4X to 12X optical zoom |
Depends on the lens |
| Somewhat important. Cameras with
greater focal range can zoom out to fit more into a shot or zoom in to fill the
frame with the subject. Optical zoom produces sharper images than digital
zoom. |
| Manual focus override |
Yes for some models, but only in stepped
increments |
Yes; some models have focus ring on lens |
Yes, with focus ring on lens |
| Somewhat important. This allows
you to focus the camera yourself, which can be more accurate than automatic
focus in some situations. Cameras with stepped focus can only be set to focus at
a few predetermined
distances. | |
Digital Camera Shopping Tips
Ready to buy a digital camera? Here are PC World's
recommendations:
- Match megapixels to your use. Most point-and-shoot
cameras offer at least 4 megapixels, which is plenty for producing 8-by-10-inch
prints. Cameras with more megapixels will yield even larger prints and allow you
to blow up a part of an image with less likelihood that the print will be
blurry. If you plan to make only 4-by-6-inch prints, you don't have to shoot at
the camera's highest resolution--and as a result, you can fit more shots on your
memory card.
- Look for rechargeable batteries and a charger. The
cost of disposable batteries adds up over the long run. Some cameras can use AA
batteries of any type--disposable or rechargeable. That capability can be
helpful if your rechargeable batteries run out of juice and you don't want to
wait while they replenish.
- Get at least 3X optical zoom. Most cameras offer
digital zoom in addition to optical zoom--and sometimes vendors combine the two
specs to tout a high total zoom. But digital zoom results in photos that aren't
nearly as good as those produced with an optical zoom.
- Look for a low-light focusing aid. Some cameras have
auxiliary lights that help them focus in dim settings. That's important for many
indoor shots.
- Try the camera before you buy. Some cameras have
commands and menus that are easier to use than others, a comparison you can make
only with a hands-on trial. Also evaluate the lag time between when you press
the shutter button and when the camera actually takes the picture. Try the zoom
lens--does it operate quickly and smoothly? Find out how long you must wait
between taking pictures. And try the LCD viewfinder--in the sun if possible--to
determine how easy it is to read.
- Give extra consideration to a camera with a good
selection of software. Look for useful packages like Adobe Photoshop
Elements and Ulead PhotoImpact for editing images, as well as applications for
sharing them.
- Don't base your decision on video capability. Any
still camera's ability to take moving pictures is limited. If you want to shoot
video, invest in a camera dedicated to the job.
- Consider investing in a memory card reader. These
readers act like an external hard drive attached to your PC or laptop, allowing
you to download pictures directly from the storage media your camera uses. Many
newer laptops have one or more memory card slots built in, as do some inkjet
printers. If you have a second memory card, you can keep shooting while the
images download, rather than having to keep the camera hooked up to your PC.
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