Digital photography

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3. CONTENTS
• If you are in the market for a digital camera,
here's the guide you've been looking for. It takes you
around and through the digital camera so you know how
it works and what its features are used for. It has
hundreds of links to the best sources and products so
you can learn even more. I Hope you enjoy it!
1. What is a Digital Photograph?
2. Why go digital?
3. Image Sensors
4. Types of Digital Cameras
5. Image Storage

4. 6. Downloading Images
7. Image Compression
8. Preview Screens & view finders
9. Lenses
10. Batteries
11. Other Features
12. Is it Time to Buy?
13. The Rules of the Shopping Game
14. Digital Photography Web Sites

5. INTRODUCTION
• Digital photography begins with capturing
images in a digital format. You can do this
by taking photographs with a film camera
and then scanning the slides, negatives, or
prints. However, it’s much faster and
easier to capture images with a digital
camera. At the moment there are many
digital cameras and new ones seem to be
introduced weekly. If you are at all like
me, these amazing devices are tempting
indeed.

6. • It’s clear that almost
everyone wants to know
more about what
features to consider
when buying a camera
and how to use those
features once they own
one. Even if you’re an
experienced
photographer, digital
cameras introduce new
criteria that you have to
consider in your buying
decision.
The Canon S20

7. Straightforward answers to the questions you might have,
including the following:
• Why go digital?
• What is a digital photograph?
• How does a digital camera work?
• What is digital photography?
• How good are digital cameras?
• What features should I look for in a digital camera?
• What resolution do I need?
• Do I want a point-and-shoot camera or one with creative
controls?
• How important are accessories?
• How should I choose the company to buy from?
• What alternatives are there to a digital camera?
• How do I use the features my camera has?

8. 1. WHAT IS A DIGITAL
PHOTOGRAPH?
• The digital photograph, is a good place to begin
understanding the whole digital photography
process.
PIXELS-DOTS ARE ALL THERE
• Digital photographs are made up of hundreds of
thousands or millions of tiny squares called
picture elements-or just pixels. Like the
impressionists who painted wonderful scenes with
small dabs of paint, your computer and printer can
use these tiny pixels to display or print
photographs. To do so, the computer divides the
screen or printed page into a grid of pixels. It
then uses the values stored in the digital
photograph to specify the brightness and color of
each pixel in this grid-a form of painting by
number. Controlling, or addressing a grid of
individual pixels in this way is called bit mapping
and digital images are called bit-maps.

9. • Here you see a portrait of Amelia Earhart done entirely
in jelly beans. Think of each jelly bean as a pixel and it's
easy to see how dots can form images.

10. Image size
The quality of a digital image, whether printed or
displayed on a screen, depends in part on the number
of pixels used to create the image (sometimes
referred to as resolution). More pixels add detail
and sharpen edges.
The photo of the face (right)
looks normal, but when the
eye is enlarged too much
(left) the pixels begin to
show. Each pixel is a small
square made up of a single
color.

11. • The size of a
photograph is
specified in one of two
ways-by its dimensions
in pixels or by the
total number of pixels
it contains. For
example, the same
image can be said to
have 1800 x 1600
pixels (where "x" is
pronounced "by" as in
"1800 by 1600"), or to
contain 2.88-million
pixels (1800 multiplied
by 1600).
This digital image of a Monarch
butterfly chrysalis is 1800 pixels wide
and 1600 pixels tall. It's said to be
1800x1600.

12. 2. WHY GO DIGITAL?
• Once captured, digital
photographs are
already in a format
that makes them
incredibly easy to
distribute and use. For
example, you can
insert digital
photographs into word
processing documents,
send them by e-mail to
friends, or post them
on a Web site where
anyone in the world
can see them.
A small digital camera is easy to
carry so you'll have it when you
see things you never expected to
see.

13. • Digital cameras are
becoming more than just
cameras. Some digital
cameras are capable of
capturing not only still
photographs, but also
sound and even video-they
are becoming more like
multimedia recorders than
cameras.
• In addition to displaying
and distributing
photographs, you can also
use a photo-editing
program to improve or
alter them. For example,
you can crop them, remove
red-eye, change colors or
contrast, and even add
and delete elements. It's
like having a darkroom
with the lights on and
without the chemicals.
Once you have captured an image in digital
format, you can easily distribute, organize,
store, and edit it.

14. THE THREE STEPS OF DIGITAL PHOTOGRAPHY
Step 1. Inputting
photographs
Input devices get photographs
or other data into a computer
system. Eg:Digital still cameras
capture photographs in a digital
format
Step 2. Processing photographs
Once a photograph is in digital form,
you can store it on your system and
then edit or manipulate it with a photo-editing
program such as Photoshop.
Step 3. Outputting photographs
Once an image is the way you want it, you
can output it to share with others. Print the
image on a color printer.

15. If you've been wondering digital photography is spreading faster than an
ordinary once, here are just some of the reasons.
• Immediately review your images on the camera's preview screen. Be more confident
because you can check your pictures immediately to see if you got what you wanted.
• Connect the camera to a TV and show your images as a slide show.
• Connect the camera to a microscope to display dramatically enlarged images on a
large-screen TV.
• Stitch together panoramas from multiple pictures of the same scene.
• Print the image on a color printer.
• Create 3D stereo images to display on the screen.
• Create animations to display on the screen.
• Save money by not buying rolls and rolls of film and paying for development.
• Save time because you don't have to make two trips to the store to drop off and then
pick up your pictures.
• Choose just the best images for printing.
• Be an environmentalist by not using the toxic chemicals used in traditional
photography.
• Don't wait to finish a roll before having it processed. (Or waste unexposed film when
you can't wait.)
• Capture sounds and even short videos with the same camera.
• Improve or alter your images with a photo-editing program.
• Hand the camera to the kids, take weird and unusual angles, shoot without looking
through the viewfinder. There are no film costs to think about.
• Insert the photograph into a word processing or desktop publishing document.
• Post the photograph on a Web site or a photo network.
• E-mail the photograph to friends or family members.
• Store the photograph on your system for later use.

16. 3. IMAGE SENSORS
•Digital cameras are very much like the still more familiar 35mm film
cameras. Both contain a lens, an aperture, and a shutter. The lens
brings light from the scene into focus inside the camera so it can
expose an image. The aperture is a hole that can be made smaller or
larger to control the amount of light entering the camera. The shutter is
a device that can be opened or closed to control the length of time the
light enters.
Film camera Digital camera

17. • The big difference between
traditional film cameras and digital
cameras is how they capture the
image. Instead of film, digital
cameras use a solid-state device
called an image sensor, usually a
charge-couple device (CCD). On
the surface of each of these
fingernail-sized silicon chips is a
grid containing hundreds of
thousands or millions of
photosensitive diodes called
photosites, photoelements, or
pixels. Each photosite captures a
single pixel in the photograph to
be.
An image sensor sits against a
background enlargement of its
square pixels, each capable of
capturing one pixel in the final
image. Courtesy of IBM.

18. When the shutter
opens, light strikes the
image sensor to form
the image.
Courtesy of Canon.
The gray scale contains a range of 256 tones from pure white to
pure black.
It may be surprising, but pixels on an image sensor can only
capture brightness, not color. They record only the gray scale-a
series of 256 increasingly darker tones ranging from pure white
to pure black. How the camera creates a color image from the
brightness recorded by each pixel is an interesting story.

19. RGB uses additive
colors. When all three
are mixed in equal
amounts, they form
white. When red and
green overlap, the form
yellow, and so on. To
see how this works,
visit Konica's
interactive presentation
by clicking the MoreInfo
button below.
WHAT IS COLOR?

20. FROM BLACK AND
WHITE TO COLOR
Since daylight is made up of
red, green, and blue light,
placing red, green, and blue
filters over individual pixels on
the image sensor can create
color images.
Colored filters cover
each photosite on the
image sensor so the
photosites only capture
the brightness of the light
that passes through. The
lenses on top of each
pixel are used to collect
light and make the sensor
more sensitive.

21. With the filters in place, each pixel
can record only the brightness of
the light that matches its filter and
passes through it while other colors
are blocked. For example, a pixel
with a red filter knows only the
brightness of the red light that
strikes it. To figure out what color
each pixel really is, a process called
interpolation uses the colors of
neighboring pixels to calculate the
two colors that the pixel didn't
record directly. By combining these
two interpolated colors with the
color measured by the site directly,
the full color of the pixel can be
calculated. "I'm bright red and the
green and blue pixels around me
are also bright so that must mean
I'm really a white pixel."
Here the full color
of a green pixel is
about to be
interpolated from
the eight pixels
that surround it.

22. There's a computer in your camera
Each time you take a picture
millions of calculations have to be
made in just a few seconds. It's
these calculations that make it
possible for the camera to preview,
capture, compress, filter, store,
transfer, and display the image. All
of these calculations are performed
by a microprocessor in the camera
that's similar to the one in your
desktop computer.

23. The CCD shifts one whole row at a time into the readout register. The
readout register then shifts one pixel at a time to the output amplifier.

24. 4.TYPES OF DIGITAL
CAMERAS
• Point and shoot cameras
– Less cost
– Automatic
– Resolution upto 3-4 million
pixels
Prosumer cameras
creative controls
5-6 million pixels

25. Digital video cameras The Sony DCR-TRV33
MiniDV
•captures 1152 x
864 pixel still
images.
•video
Specialty cameras
Cell phones like this one
from Nokia are now
featuring built-in
cameras.
Novelty Cameras
Casio makes a
camera watch
that can capture
small images up
to 176 x 144
pixels and can
store about 100
of them

26. 5. IMAGE STORAGE
Flash card storage
Memory card storage cases
Hard disk storage
Optical disc storage
Temporary Storage

27. 6. DOWNLOADING
IMAGES
Cables. Most cameras now come with a USB or FireWire port that you
can use to connect the camera to the computer with a thin cable.

28. 7. IMAGE
COMPRESSION
• What is compression?
• During compression, data that is
duplicated or that has no value is
eliminated or saved in a shorter
form, greatly reducing a file’s size.
• There are two forms of compression
—lossless and lossy—and digital
cameras use both forms.

29. 8. PREVIEW SCREENS &
VIEWFINDERS
LCD monitors
let you see the
image you just
took and scroll
through those
stored in the
camera.
Some cameras have
monitors that swing
out and swivel so you
can position it at
almost any angle--
even facing frontward
for a self portrait

30. 9. LENSES
Focal length
• One of the most important characteristics of any lens
is its focal length. It's the focal length that
determines a lens' angle of view-wide angle, normal, or
telephoto.
As the focal length of a lens increases, its angle of view decreases.
Here the short focal length lenses are on the left and the long focal
length lenses are on the right. As you move from left to right the focal
length increases and the field of view decreases.

31. 10. BATTERIES
The best batteries for
cameras that accept AA
batteries are clearly NiMH
(nickel-metal hydride).
Battery charger
Some cameras come with
their own chargers, but you
might be able to find a better
one with more features.

32. 11. OTHER FEATURES
Look and feel
Size and weight
Orientation sensor

33. Panorama mode
Some panoramas are
created by throwing
away much of the
captured image. (The
black bands shown
here.) When just the
central strip is printed, it
looks panoramic.
Multiple exposures
This double-exposure puts
Clover the cat next to the
woman hiding behind the
sheet of paper.

34. With addition to the above the
following are some other
features that should be noted.
Self-timer/remote control
Date/time indicators
Sound recording
Image modes
and
Software
Photoshop is the photo editing
program against which all others
are compared.

35. 12. IS IT TIME TO BUY?
Point to Consider Digital Camera Scanned Film
Immediacy Images are instantly available Images are available only after the
roll is finished and processed
Resolution Resolution (detail) is low compared
to film. Even digital cameras with
over 1 million pixels are only great
for 4 x 6 prints and good for 8 x
10s.
Excellent, many times higher than
digital cameras. You can make 16 x
20-inch prints from 35 mm film if
you shoot with a tripod.
Storage Magnetic or optical media adds to
total image costs.
Negatives and slides are self
storing, but slides must be put in
sheet holders for protection,
convenience, and ease of use.
Longevity Storage media may not be
readable in the future as formats
and devices change. Prints are not
as stable as silver-based prints.
Slides and prints can always be
viewed without devices; and slides,
negatives, and prints should easily
last a century or more.
Cost Film and processing cost is
eliminated so you can shoot at no
cost. However, costs are incurred
when you store or print. Battery
costs will also be a factor over the
life of the camera.
Film must be both purchased and
processed. However, at that point
there are no additional costs unless
you want additional prints or
enlargements.
Creative Controls All but the most expensive
consumer level digital cameras lack
all of the controls found on the
least expensive SLR cameras.
Choice of lenses is very limited.
Professional level controls are
found on even the cheapest 35 mm
SLR. There is also an extensive
choice of lenses for most models.

36. 13. THE RULES OF THE SHOPPING GAME
Advertising claimsCheck Reseller Rankings
Check price comparison sites
Explore on-line auctions
Watch out for unbundling
Avoid gray market products
Check postage rates
Avoid extended warranties
Check return policies, restocking fees
Buy no extras
Shop locally-support your local economy

37. 14.Digital photography
Web sites
Steves Digicams
Steve Sanders runs one of the most popular sites on
the Web. Not only does he have up-to-the-minute
news, his discussion forums are among the most heavily
visited. This is a must visit for anyone exploring thew
world of digital photography.