Create high-quality images with Digital cameras
Digital cameras have recently grown in popularity because of
their increasing image quality and easy interaction with desktop
PCs. Digital cameras create high-quality images that allow you
to send to others over the Internet or print on a color printer.
Red Hat Linux supports several brands of digital cameras and has
applications that help you access, view, and modify your digital
photographs.
digital camera has many advantages. It saves you money in the
long run because you don't have to buy rolls and rolls of film
and you don't have to pay for development. You don't have to go
to the store to drop off an then pick up your pictures. A
digital camera shows you the images before they are printed, an
if you don't like it, you simply delete them. Digital
photographs are incredibly easy to distribute and use. You can
insert them into word processing documents, send them to friends
by email, or place them on a website where anyone in the world
can seem them. You can also connect your digital camera to the
TV and show them like a slide show. It's like instant
photography without the film costs. You can also use
photo-editing programs to improve your pictures. Red eyes are
easily removed, you can change colors or contrasts, element can
be deleted or added... It's like a darkroom without the
chemicals. Some digital cameras are also capable of capturing
sound an video. They are so useful that they are being
incorporated into more and more devices like PDAs and cell
phones. This way you can send your images to other phones or
post them on the internet.
Digital cameras have recently grown in popularity because of
their increasing image quality and easy interaction with desktop
PCs. Digital cameras create high-quality images that allow you
to send to others over the Internet or print on a color printer.
Red Hat Linux supports several brands of digital cameras and has
applications that help you access, view, and modify your digital
photographs.
Shopping for a digital camera can be a difficult task
considering the sheer number of choices out there. The number of
manufacturers, models, and price ranges that need to be sorted
out make the process difficult enough, but throw in all the
buzz-words that need to be understood, and even a short list of
cameras can become difficult to analyze.
This Tech Tip will take a look at a few key words that may come
up when researching a digital camera, and will hopefully reduce
the headaches associated with the process.
Pixels
Digital images are composed of thousands or millions of tiny
squares called picture elements, or pixels for short. Each
square has its own color assigned to it, and the compilation of
all of these little colored squares allows for images to appear
smooth when viewed at original size. If an image is magnified
several times, the appearance of the pixels can become more
obvious, and at high magnifications each colored pixel can be
distinguished individually.
Megapixels
Basically, the term megapixel means one million pixels, and it
is used to describe the maximum number of pixels found in an
image produced by a digital camera. It is generally the criteria
used to classify cameras, and checking the Geeks.com selection
(http://www.geeks.com/products.asp?cat=CAM) shows that their
cameras are all sorted into ranges of megapixels (MP).
Many people assume that because cameras are marketed so heavily
by their megapixel specification, that this is the single most
important criteria when choosing a camera. More megapixels do
not necessarily equal better images, they mean larger images
(both in physical size and in file size).
The megapixel count is achieved by multiplying the number of
pixels in one horizontal line by the number of pixels in one
vertical line. So, if a camera can produce images at a maximum
resolution of 1600 by 1200 pixels, it is a 1.92 megapixel
(1,920,000 pixel) camera.
It is not fair to assume that the images from the 5.0 MP Kodax
CX7525 are automatically better than those from the 4.0 MP Kodak
CX7430 strictly based on their megapixel count. All it means is
that the maximum image size of the CX7525 is 2560 x 1920 and the
maximum image size of the LS743 is 2408 x 1758. Many other
features in the cameras can impact the quality of the images
they produce, and may be far more important for the typical user
to consider than the maximum overall size of each image.
Larger image size may do nothing for a user who only wants to
view images on his computer screen, or for use on the web, but
the higher megapixel images are important for those looking to
make prints of their images. Generally, higher pixel counts in
an image translate to the ability to create larger prints.
Sensors - CMOS and CCD
Digital cameras use a small sensor to capture the image before
transferring it to flash memory for storage. Equivalent to a
negative in a film camera, these sensors come in a variety of
sizes, with most being between 20 and 40 millimeters squared.
There are two types of sensors that may be found in cameras: CCD
(Charged Couple Device) and CMOS (Complementary Metal Oxide
Semiconductor). CMOS sensors are usually found in cheaper
cameras and offer lower image quality than a CCD sensor that
would probably be found in a more expensive camera.
There is an exception to the rule that CCD is better than CMOS,
and that is with the Digital SLR-type (Single Lens Reflex)
cameras. They use a much larger sensor (greater than 300
millimeters squared) and can provide excellent image quality,
but the quality does come with a much higher price tag.
Zoom - Optical and Digital
Most digital cameras offer some sort of zoom, but it is
important to identify which type is being provided. Optical zoom
functions just as on a film camera, where the lens physically
moves to produce the magnification. Digital zoom uses circuitry
to enlarge a portion of the standard sized image and crops the
content outside of the zoomed area. The quality of images
produced using digital zoom suffer due to the nature of the
process, and optical zoom is a far more desirable feature.
The price of a camera with optical zoom may be a good deal more
than one with digital zoom, but the quality of the images cannot
be compared. The Kodak CX7330 and the Kodak CX7300 are
comparable cameras in many regards, but the CX7300 features only
digital zoom, while the CX7330 features both optical and digital
zoom for about $30 more.
Memory - Digital Film
The two important things to consider when choosing flash memory
for a digital camera is that the right format is chosen, and
that a quality module is chosen that can record quickly and be
ready for the next picture as soon as possible. A photographer
looking to snap a rapid series of high resolution images on
their Kodak DX7440 has many options in SD (secure digital)
memory to choose from but, they would be far better off with
something like the SanDisk Ultra II SD card capable of a
sustained write speed of 9 MB/s, than with a generic SD card
capable of a burst speed rated at only 2.5MB/s.
Aliasing
Even if you think you know the basic definition of this term, it
may seem confusing in the context of digital cameras. Aliasing
refers to the appearance of jagged edges generally seen on
diagonal or curved surfaces in images. This effect is caused by
the fact that all pixels are square, and that even non-square
shapes in an image need to be created with square components.
The solution to aliasing is not surprisingly called
"anti-aliasing." Through software, the edges generally affected
by aliasing are blended and the jagged appearance can be made
much smoother. Video game enthusiasts may be familiar with
anti-aliasing and the impact the varying levels of it can have
on the overall performance of game play. Although the technology
is similar, the personal importance of having the best digital
images possible makes applying anti-aliasing just about a
no-brainer.
Aspect Ratio
Aspect ratio describes the shape of a digital image, or any
image for that matter, where the first number represents the
width of the image and the second number represents the height.
People may be familiar with the term as applied to televisions
(as 16:9 wide screen televisions are now all the rage to replace
traditional 4:3 units), and the concept is the same here.
Standard film cameras generally use an aspect ratio of 3:2, but
most digital cameras have adopted a 4:3 aspect ratio so that
images better fit on a standard computer monitor. Monitors with
typical resolutions of 800x600, 1024x768, or 1280x960, for
example, all have an aspect ratio of 4:3, so it only makes sense
to produce images that will fit well on these screens. Although
images can be manipulated to print on any size paper, special
photo-quality paper is available to allow for high-quality
prints to be made at the correct aspect ratio.
Connectivity
The pictures taken by a digital camera have to be extracted by
some means in order to get them onto a computer, or perhaps
directly onto a printer. In general, cameras provide a cable to
connect to a computer either via serial, USB, USB 2.0, or
Firewire.
Serial ports are just about extinct at this point due to their
slow connection speeds and lack of plug-and-play support, but
some older or lower-end models may still offer serial
connectivity.
USB may be the most common form of connectivity, and if speed is
important to you, look specifically for USB 2.0 support, as it
is up to 40 times faster.
Some specialized cameras may take advantage of the high speed
Firewire protocol for connecting to a computer. Just about all
modern computers come with at least a pair of USB ports, but not
all computers include Firewire. Firewire capabilities can be
added to any computer with an available PCI slot by using an
expansion card such as this one.
Some cameras don't require any cables at all, as they can
transmit the images to a PC wirelessly. The Concord EyeQ is such
a camera that utilizes Bluetooth technology in lieu of wires.
Even with all the modes of transmitting images listed so far,
one other method may serve as a universal replacement for all of
them. Many people find flash memory card readers to be a quick
and convenient alternative to using the camera's native means of
connecting. You simply remove the memory from the slot on the
camera and pop it into the appropriate slot on the reader, and
then the computer system can access the card like a local disk
drive.
Final Words
Every high-tech field has its own set of specific buzz words,
and digital photography is no different. Although by no means an
exhaustive resource of digital photography terminology, this
Tech Tip provides insight to a few key terms worth knowing in
order to make shopping for a digital camera just a bit easier.
For more information on Digital Camera please visit the Digital Camera resource center.