Digital Camera Basics
What's the most obvious difference between a digital and a conventional
camera? That's easy: no film. Instead of film, digital cameras use tiny memory
cards to store images. This means no environmentally messy chemicals that can
leak into the environment. If you think green is good, digital photography is
for you.
Storing images electronically instead of on film has other advantages. First,
digital media storage is more convenient than traditional 35 mm canisters. Some
memory cards can hold hundreds of high quality images, and you never have to
worry about using the wrong film or airport X-ray security devices ruining
undeveloped pictures.
Second, digital cameras offer a wide range of resolution possibilities. A
digicam's imaging surface is made up of tiny sensors that transform light into
electronic data called pixels. More sensors equal more pixels, which means
sharper (more finely detailed) pictures. A camera that captures an image with
640 horizontal pixels by 480 vertical pixels has a resolution of 640 x 480, or
307,200 pixels. It takes a resolution of about two million pixels (two
MegaPixels) for a digital photo printed at 8" x 10" to be indistinguishable from
a photographic print. But high resolution isn't always needed. If you want
smaller prints, 640 x 480 may be fine, and since computer monitors can't display
high-resolution images, low-resolution digital cameras are perfect for images
destined to be distributed only via email or viewed on a web site.
The third big advantage is that digital cameras can offer all the creativity
of traditional film cameras, such as rapid sequential shooting, panoramic
scenes, and time-lapse effects, but with immediate results you can view on the
spot. Add to this the ability to capture sound, and even short motion video, and
you can easily see how you'll achieve spectacular results with digital
photography.
Important issues to consider
How do you choose the right camera? For starters, it's important to
understand some of the technical issues associated with digital cameras and how
they relate to your budget and what kind of pictures you plan to shoot.
Resolution
The issue of resolution isn't as simple as high vs. low pixel count. When
specifying resolution you have to know the difference between optical and
interpolated resolution. Think of optical resolution as real resolution - the
actual number of sensors in the digicam's array. The "rule of thumb" with
optical resolution is that the higher the resolution, the more expensive the
camera. Interpolated resolution uses a mathematical algorithm in the camera's
computer processor to insert pixels into a low-res image to make the resolution
appear higher. What it really does is make an educated guess at filling in the
missing pixels, and this results in unwanted "artifacts" in your pictures.
Every month digital camera manufacturers are releasing higher resolution
cameras at lower costs. Choose a camera in your price range that offers the best
optical resolution, and don't put a lot of stock in a camera's interpolated
resolution claims. The same holds true, as you will learn in a moment, for the
camera's lens: an optical zoom lens is a camera's true measure of quality, and
digital "interpolated" zoom capabilities should be considered a low-quality
novelty feature.
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Lenses
Here's an issue that in many ways applies to both traditional and digital
photography. Aside from the quality and resolution of the CCD sensor, your
digicam's lens may be the single most important influence on the quality of your
pictures. So go with a camera with the best optical zoom lens you can afford.
And don't rely on digital zoom: the farther you zoom in, the more unwanted
artifacts you get. Some cameras also let you mount special lenses, such as
wide-angle and telephoto extenders. If you are interested in these accessories,
find out which cameras accept them from the manufacturer.
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Compression
To understand digital photography you have to understand a little about
computers. Like everything else in a computer, digital images are stored as
files, and the higher the resolution the bigger the file. Most digital images
are compressed in the camera using JPEG encoding (when you see an image file in
your computer it will have a .JPG file extension.) To prevent your hard drive
from filling up you have to be aware of image size, resolution and compression.
Compression is typically expressed as a ratio: 1:4 (fine), 1:8 (normal), 1:16
(basic). For image quality, the less compression the better - particularly when
you shoot big pictures at high resolution. Compressing a raw (uncompressed)
image can make it 4 - 20 times smaller, so it takes up less space in your
storage media. But compression works by taking details in your digital image and
- literally - throwing them away and replacing them with patterns the
compression process creates itself. More compression means more unwanted stuff
in your pictures. So when you select a compression level you are really trading
off quality for space.
Some newer cameras can shoot in an uncompressed TIFF mode. This will really
eat up the memory in your camera and your hard drive, but it preserves the
cleanest image for use in print or applications where the image may be edited.
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Light
The good news is that most digital cameras have fast lens apertures, which
help them take good pictures in relatively low light. But no camera likes to
take pictures in really low light without a flash. More good news: most digicams
have a built-in flash, and some allow you to use an external flash, which is
many times more effective than a camera's built-in flash and helps preserve the
camera's battery.
Many low to medium-end digital cameras offer only one pre-set light
sensitivity, usually between ISO 50 and ISO 200. But you can usually increase
the ISO by adjusting the exposure compensation controls. Like film cameras,
though, high ISO equals a grainy picture and a lower minimum aperture allows
sharper pictures - especially in low light.
Another plus for digital cameras is that digicam lenses provide tremendous
depth of field, so even with the aperture wide open subjects both near and far
remain in focus. Many digital cameras also have a Macro focusing feature, which
permits you to clearly photograph objects only inches from the lens.
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Batteries
Digital cameras really go through batteries, and there's nothing worse than
losing shots of an important event because of a dead battery. One simple tip — always
bring extra batteries. Most cameras allow you to charge the battery through the AC adapter
while it's in the camera. Since this can take up to eight hours, you may want a separate
charger which can fully charge a battery in less than an hour — without tying up your camera.
If your digital camera supports AA batteries, read the camera manual and check to see if it
also supports NiMH (nickel metal hydride) batteries. As far as batteries go, NiMHs are your
best bet because they last the longest and don't have to be fully discharged before recharging.
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Memory Cards
Most digital cameras use removable storage cards and come standard with a 64MB (or less) memory card.
Consider upgrading and get as much memory as you can afford: 1 GB cards will give you plenty of storage
for a long trip or big family event. SmartMedia™ and CompactFlash™ are both good choices. Just remember
to never insert or remove a memory card while the camera's power is turned on, or you may lose your images
or damage your card. After the card is properly inserted, you can turn on your camera and start shooting.
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Shooting Tips
With all these great features, taking pictures with a digital camera should
be a breeze, and for the most part it is. After all, your camera will
automatically focus and balance different colors, and it does a good job in low
light conditions. But there are a few little quirks you'll have to get used to
if you want the best results:
1. Hold still. Some cameras have only an LCD monitor for viewing, which means
you have to hold the camera away from your face to see what you're shooting.
It's hard to keep still in this position, but you have no choice unless your
camera has a conventional optical viewfinder. Hold the camera in both hands, and
place your elbows in against your chest to steady it. Or lean against a wall,
pole, tree, etc.
2. You will undoubtedly notice a time lag between pressing the shutter
release and the exposure. This delay is necessary because your camera needs a
little time for pre-shot calibration and to balance the colors. Just hold the
camera steady for a little longer than usual until you get used to the time
delay.
3. There is also a delay between shots as the camera processes the previous
images. Some new cameras have buffers that let you continue shooting during the
processing time, which is great for fast action photography. If your camera
doesn't have a buffer you'll have to wait between shots, so look for a camera
with fast shot-to-shot time.
4. If your camera lets you to override the autofocus, you'll want to use this
feature if you take a lot of action shots, or if you are shooting through glass.
Even if your camera has a buffer, the autofocus may not react fast enough to
give you sharp pictures if you shoot too quickly or the light is too low.
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Transferring your photos to a computer
So you've taken some great shots. You know they look great because digital
cameras let you see them right away! But now it's time to get your pictures out
of the camera, and there are several ways transfer JPG files to your computer.
The most common is via a cable that hooks into the serial port of your computer.
Cameras come with software that lets a computer "talk" with the camera and
retrieve pictures. A much faster way to transfer images into your computer is
through a USB or Firewire port. These ports are similar to a serial port, but
can send data at a much faster rate.
Another way to get images into your computer is via a card reader. A card
reader is a small external or internal device that accepts your memory card.
Card readers can transfer photos at speeds up to 1MB/second - many times faster
than transferring from your camera. You can also use adaptors, which let you
insert memory cards into your computer's floppy drive.
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Archiving your photos
Now that your photos are safely tucked away in your computer, what's the best
way to file, manipulate and sort them? If you take a lot of pictures, this can be
a thorny problem because as far as eating up drive space is concerned, digital
images are real hogs. Plus, you have to organize digital photos for the same
reason you have to organize conventional photographic prints: if you don't, you
can't find what you want without dumping a pile of pictures on a table and
sifting through them.
Sure, you can buy a few expensive removable drives and try to organize your pictures
into files and folders on your computer, but dotPhoto gives you a better alternative.
You can eliminate the archiving and drive space nightmare by simply uploading your pictures
to dotPhoto. You can use dotPhoto's advanced Internet tools to organize your photos into albums,
add text and voice messages, and share your photos with family, friends and business associates
anywhere in the world. Best of all, uploading and storing your photos is FREE (there are some storage
limits for photo resellers) and there's no limit to how much you can store. You can even order 35mm quality
prints of your photos with a few mouse clicks. So check out dotPhoto's membership options and see for yourself
how dotPhoto.com can make your digital photography experience even more rewarding.
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