Nothing’s super about superfluous pixels

Nothing’s super about superfluous pixels
If you think you can never be too rich, too thin, or have too many megapixels,
think again. Megapixels have a dark side, too, Luke. Unnecessary pixels
lead to bigger image files, usefulewhen you actually need all those pixels, but
they’re a potential nuisance if you don’t. Few people have the problem of
being able to afford a camera that has a resolution significantly higher than
they really need, but if you’re in that elite class, consider these caveats:

1. Excess megapixels eat up your memory cards. All dSLRs store images on
solid-state memory cards. I own three cards for my 10MP camera, each of
which can store about 272 pictures in the best high-resolution shooting
mode. Most of the time, I have plenty of digital film for any day’s shooting,
and I can always drop to a lower resolution mode to stretch my memory
cards further. However, if I used the same vendor’s top-of-the-line 24.5MP
dSLR, each of those cards could hold only 85 images at the top quality setting.
I’d have to own a lot more memory cards to do the same work!

2. Extra resolution taxes your computer. Fat photo files take a long time to
transfer to your computer, and your image editor needs fast processing
speeds and a lot of memory to manipulate those files. That high-end digital
camera that you’re lusting after might call for a high-end computer, too.

3. More pixels need more storage. Very high-resolution files can be several
times larger than your run-of-the-mill high-resolution image files. If
you want to keep a lot of these files available on your hard drive, you
need a large disk — and probably a lot of extra CDs, DVDs, or external
hard drives to which you can archive them for permanent storage.

Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

Deciding how many pixels your camera needs

Deciding how many pixels your camera needs

People contemplating the purchase of a digital SLR often agonize over how

many megapixels they should buy, even though you may find other factors

(such as ease of operation and the kind and quality of lenses available for a

particular dSLR) considerably more important in the long run. To a certain

extent, vendors have (at least temporarily) alleviated this agony. In the past

year or two, a surprising number of vendors have settled on 12MP as a basic

benchmark number.

Nikon, for example, has three 12MP digital SLR cameras — a basic entry-level

model, an intermediate amateur camera, and a feature-packed advanced

model that both serious amateurs and professionals love. Canon, too, has

introduced several 12MP models, and other vendors have followed. Of

course, for most applications, you don’t really need more resolution. But,

with competitive pressures being what they are, I don’t know just how long

the 12MP plateau will remain the standard. (I urge those of you reading this

in 2012 with your $499 21MP cameras to refrain from laughing.)

Although more pixels usually equal more resolution and more detail in your

pictures, the number of pixels you actually need depends on several factors:

1. How you plan to use the photo: An image that you place on a Web site

or display in presentations doesn’t need to have the same resolution as

one that you use professionally — for example, as a product advertisement

or a magazine illustration.

2. How much manipulating and cropping you plan to do: If you want

to give your images quite a workout in Photoshop or you often crop

small sections out of images to create new perspectives, you want all

the spare pixels that you can muster because high-resolution images

can withstand more extensive editing without losing quality than lowresolution

images can.

3. How much you plan to enlarge the image: Many people view most of

their images on a computer display or in 4-x-6-inch to 5-x-7-inch prints.

Any dSLR has enough megapixels for those modest applications. If

you’re looking to make blowups bigger than 8 x 10 inches (for example,

to make posters or prints that you display on the wall), you need a

plethora of pixels.

4.The resolution of your printer: Most digital images are printed on

inkjet or dye sublimation devices that have their own resolution specifications,

usually from 300 dpi (dots per inch) to 1440 dpi and beyond.

Printers work best with images that more closely match their own

ability to print detail.

If you primarily want to create prints, the following section can help you

gauge which capabilities you need in your camera and printer so that you

can get the best output possible.

Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

Megapixels and Why dSLRs Have More of Them

Megapixels and Why dSLRs Have More of Them

If you’ve been working with digital images for a

while, you know that pixels are your pals. They’re

the basic building blocks that make up an image. The

term pixel is a portmanteau, which was Lewis Carroll’s

term for a new word created by combining two old

words, such as slimy and lithe to create slithy. In this case,

pixel stands for picture element and came into vogue when

computer imaging became popular.

However, you’ve seen pixel-like components outside the digital realm, in

pointillist paintings, such as the illustrations Georges Seurat created for the

Broadway musical Sunday in the Park with George. You also see pixel-like

components in newspaper halftone photos. All these images are made up of tiny dots that you can see vividly up close, but those dots blend to create

continuous tones and colors when you view them from a distance,The difference between these picture elements and those used to represent digital photos is that the digital pixels are all the same size

and shape, varying only in brightness and hue.

In digital images, the pixels — tiny squares that you can see individually only

under magnification — are arranged in rows and columns like a checkerboard

that happens to measure hundreds of squares on a side. Among current digital

SLRs, this array is a minimum of 3,008 pixels wide and 2,000 pixels tall,

for a total of 6 million pixels in all. (Although the last of these 6-megapixel

cameras will probably be phased out early in the life of this book.) The latest

digital SLR cameras for consumers actually offer many more pixels than that,

from 3,872 x 2,592 (10 million) pixels for certain entry-level models to 4,288

x 2,848 (12 million) pixels or more for the majority of digital SLRs. Of course,

pro and advanced amateur cameras go up to 6,048 x 4,032 (24.5 million)

pixels. That’s a lot of pixels! Those pixel counts represent the number of light-sensitive areas in the

digital camera’s sensor, and the total is usually expressed in terms of megapixels

(millions of pixels), and abbreviated MP. The precise dimensions

might vary, depending on the exact sensor used. For example, the Nikon D40

uses a 3,008-x-2,000-pixel sensor, but the original Canon Digital Rebel had a

3,072-x-2,048-pixel array. Both cameras were considered 6MP dSLRs, even

though the arrangement and number of pixels is slightly different.

Pixelementary, my dear Watson

Pixels, represented by individual

light-sensitive areas in a sensor

called photosites, capture the detail

in your image. In general terms,

the more megapixels, the better

because when you add pixels, the

ability of the sensor to capture detail

improves and the effective resolution

of the sensor rises.

It’s like dividing a foot-long ruler into

1,200 increments rather than 120.

In the former case, the ruler could

measure things with 1/100-of-an-inch

accuracy; in the latter, you could

use the rulings only in 1/10-of-an-inch

chunks. In the same vein, a sensor of

a particular size that has 12MP can

show much finer detail than one the

same size that has only 6MP. when

the size of the pixels decrease, more

of them can fit on a sensor to capture

ever smaller details of the original

image. However, image quality

involves more than resolution alone.

Many 10MP dSLRs produce sharper

and more noise-free results than

12MP non-dSLRs simply because the

10MP dSLR’s sensors are physically

larger and each individual pixel is

better than a non-dSLR’s sensor’s.

Some dSLRs even outperform other

dSLRs that have more resolution

because of the quality of the sensors,

lenses, or electronic circuitry in the outperforming dSLR. For example, I have a 12MP pro dSLR that consistently

produces better results than a 14MP entry-level model from another vendor,

particularly under lower light levels. The raw number of megapixels gives

you only a guideline, even though the more pixels, quite often the better your

images look.

Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

A closer look at shutter lag

A closer look at shutter lag
Typically, the snapshooter can finally coax a
niece or nephew into smiling and press the shutter
release to capture the moment. Or a batter
swings lustily at a fat pitch and lofts the gamewinning
run into the stands just when the photographer
presses the shutter button. However,
the crucial moment is never captured on pixels.
Instead, the digicam’s autofocus and autoexposure
mechanisms make some last-minute
adjustments, a bunch of electronic components
process some algorithms, and (eventually) the
camera takes the picture. This period of time is
measured in ohnoseconds; ohnoseconds are
the interval between when you want to take the
picture and when you actually hear the shutterclick
sound that your camera emits. I’ve tested
hundreds of digital cameras, and the actual
elapsed time for non-SLRs ranges from 0.6
seconds to 1.2 seconds under bright, contrasty
lighting conditions, or up to 1 to 2 seconds in
dimmer lighting. It just seems even longer than
that.

Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

A dSLR works like a camera

A dSLR works like a camera

Another reason why digital SLRs have improved performance is that they’re

easier to use, so you, as the photographer, can work quickly while you shoot.

The manufacturers configure most point-and-shoot cameras for consumers

who simply want to grab a quick snapshot, instead of investing some artistry

in creating a photograph.

Moreover, point-and-shoot cameras tend to be designed by an engineer who

did a really, really good job adding photo capabilities to the vendor’s cellphone

line last year, and who obviously must be the best choice to cobble

together a full-fledged digital camera. Indeed, the line between cell-phone

cameras and digital snapshot cameras is blurring all the time. (I predicted a

few years ago that soon photographers would be able to get only two kinds of

cameras: cell-phone-integrated point-and-shoot cameras and digital SLRs.)

Like a cell phone, non-SLR digital cameras tend to have most of the controls

tucked away out of sight in the menu system, where the average consumer

never has to see them and where the photo enthusiast has to hunt for them.

Digital SLRs, on the other hand, are always designed by a team of engineers

who have extensive photographic experience. They know which controls a

photographer absolutely needs and which controls they can bury away in the

menus because you access those controls only when setting up the camera

and maybe once a month (if that) thereafter.

Digital SLR designers know that you don’t want to go three levels deep into a

menu to set the ISO sensitivity or adjust white (color) balance for the type of

illumination that you’re using. You want to press an ISO or a WB (white balance)

key and dial in the setting without giving it much thought. You don’t

want to activate an onscreen display to set shutter speed or aperture — you

want to have separate dials for each. Nature intended that you zoom and

manually focus your camera by twisting a ring on the lens — not by pressing

a little lever and letting a motor adjust the lens at its own pace.

Simply having a camera that operates like a camera, rather than like a DVD

player, makes your picture-taking much easier and faster.

Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

Taking photos faster

Taking photos faster

Everything about a digital SLR seems to work more quickly and responsively.

You may find that speed important when you want to make a grab shot on

the spur of the moment or expect the camera to take an action photo right

now when you press the shutter release at the peak moment. Many pointand-

shoot digital cameras are downright sluggardly compared to dSLRs when

it comes to performance (although some vendors have worked very hard

to close the gap). You can find improved speed in three key areas, which I

explain in the following sections.

Wake-up time

You can have a relatively fast non-SLR digicam powered up and ready to snap

its first photo in as little as two seconds. Many of these cameras take three

to four seconds to emerge from their slumber. Worse, because they consume

so much power (thanks to the rear-panel LCD), these cameras may go into

stand-by mode or shut off completely if you don’t take a picture for 30 to

60 seconds.

When you flip the power switch of a dSLR, the camera is usually ready to

take the picture before you can move the viewfinder up to your eye. Some

dSLRs are ready to go in 0.2 of a second! Digital SLRs don’t need to go to

sleep, either, because they consume so little power when not in active use.

I’ve left dSLRs switched on for days at a time with little perceptible draining

of the battery (but not in Live View mode, of course). Certainly, the autofocus

and auto-exposure mechanisms go on standby a few seconds after you move

your finger from the shutter release, but you can have them available again

instantly by giving a quick tap to the button.

Shot-to-shot time

Conventional digital cameras have limits on how quickly you can take pictures

in succession. Unless you’re using the motor-drive-like burst mode, one

shot every second or two is about all you can expect. Even in burst mode,

you’re lucky to get much more than one to three frames per second for 5 to

11 shots, max. Some point-and-shoot cameras do allow you to fire off shots

continuously for longer periods (in some cases, until the memory card is

full!), but you don’t find such speediness in the average entry-level digital

snapshot camera.

But all digital SLRs have relatively large amounts of built-in memory that

temporarily store each photo that you snap before the camera transfers it to

your memory card at high speed. You can probably take pictures in singleshot

mode as quickly as you can press the shutter release, and for at least

eight to ten shots before a slight pause kicks in. If you use a fast dSLR that

has some quality level settings, you can often keep taking pictures for as long

as your finger (or memory card) holds out.

A dSLR’s burst mode can typically capture three to nine frames per second

for 12 to 30 shots, depending on the speed of the camera and the quality

level you choose — low quality (high compression) settings produce smaller

images that the camera can write to the memory card quickly .

No common point-and-shoot camera comes anywhere close to that level of

performance at full resolution, even though a few can shoot at sustained frame

rates that allow you to produce movie-like effects with your still images.

Shutter lag

When I’ve spoken before groups promoting my other books, such as Digital

Photography All-in-One For Dummies, 4th Edition (Wiley Publishing, Inc.),

here’s the number one question I get from new digital photographers —

“What can I do about shutter lag!?!” Digicam owners seem to really dislike

their camera’s shutter lag — the pause between the moment you click the

shutter button and the moment the sensor captures a slightly different

image. Some snapshot cameras are worse than others, of course, but you can

still find many models available that produce an annoying lag between pressing

the button and taking the picture.

Digital SLRs also experience shutter lag, but it’s likely so brief — on the order

of 0.1 to 0.2 of a second — that you never notice it. Of course, dSLRs have

little shutter lag only most of the time. Point your lens at a difficult-to-focus

subject, such as the sky, or try to take a photo under low light, and your

speedy autofocus lens might hunt back and forth while you gnash your

teeth in frustration. 

 Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

Flexing the powerful sensor of the dSLR Camera

Flexing the powerful sensor of the  dSLR Camera
With very few exceptions, digital SLR sensors are much bigger than their
point-and-shoot camera counterparts, and this size gives them a larger area
that can capture light and, potentially, great sensitivity to lower light levels.
(Some non-SLR cameras give up compactness to provide somewhat larger
sensors, but they’re still fairly rare.)

A dSLR’s extra sensitivity pays off when you want to
1. Take pictures in dim light.
2. Freeze action by using shorter exposure times.
3. Use smaller lens openings to increase the amount of subject matter
that’s in sharp focus.

Within the Canon digital camera
line alone, you find digital SLRs that
have 22.2mm-x-14.8mm to 24mm-x-
36mm sensors (the size of a 35mm
film frame). By comparison, some
of Canon’s digital point-and-shoot
cameras use a sensor that measures
only 7.8mm x 5.32mm. Put in terms
that make sense to human beings,
the dSLR sensors have 8 to 20 times
more area than their Lilliputian
point-and-shoot sensor-mates.

If you think of a sensor as a rectangular
bucket and the light falling on
it as a soft drizzle of rain, the large
buckets (or sensors) can collect more drops (or the particles of light called photons) more quickly than the small ones. Because a certain minimum
number of photons is required to register a picture, a large sensor can collect
the required amount more quickly, making it more sensitive than a smaller
sensor under the same conditions.
In photography, the sensitivity to light is measured by using a yardstick
called ISO (International Organization for Standardization). Most point-andshoot
digital cameras have a sensitivity range of about ISO 50 to ISO 100 (at
the low end), up to a maximum of ISO 800 to ISO 3200 (at the high end). Some
point-and-shoot models have even higher sensitivity settings, but it remains
to be seen how useful these ultra-high ISO non-SLR models are. Indeed, many
models that have high ISO settings generally don’t do a very good job in
terms of image quality.
In contrast, digital SLRs — which have more sensitive sensors and larger
light-gathering pixels — commonly have usable ISO settings of up to at least
ISO 1600. Many are capable of ISO 3200 or may range up to a lofty ISO 25600!
This extra speed does have a downside, as you can see in the following section.
But, in general, the added sensitivity allows people to shoot photos in dim
light, take action pictures, or stretch the amount of depth-of-field available.
Reducing noise in your photos
Visual noise (or just noise) is that grainy look that digital photos sometimes
get, usually noticeable as multi-colored speckles most visible in the dark or
shadow areas of an image. Although you can sometimes use noise as a creative
effect, it generally destroys detail in your image and might limit how
much you can enlarge a photo before the graininess becomes obtrusive.
The most common types of noise are produced at higher sensitivity settings.
Cameras achieve the loftier ISO numbers by amplifying the original electronic
signal, and any background noise present in the signal is multiplied along with
the image information.
Point-and-shoot digicams often don’t have ISO settings beyond ISO 1600
because the noise becomes excessive at higher ratings, sometimes even
worse than you see . However, you can
boost the information that the big dSLR sensors capture to high ISO settings
with relatively low overall noise. I’ve used digital SLRs that had less noise at
ISO 1600 than some poor-performing point-and-shoots displayed at ISO 400.
Obviously, the large sensors in dSLRs score a slam-dunk in the noise department
and make high ISO ratings feasible when you really, really need them.

Noise doesn’t always result simply from using high ISO settings: Long exposures
can cause another kind of noise. Although some techniques can reduce
the amount of noise present in a photo (as you can discover in Chapter 2), by
and large, digital SLR cameras are far superior to their non-SLR counterparts
when it comes to smooth, noise-free images.
Thanks to the disparity in size alone, all sensors of a particular resolution
are not created equal, and sensors that have fewer megapixels might actually
be superior to high-resolution pixel-grabbers. For example, most older
10-megapixel dSLRs produce superior results to some of the newest
12-megapixel non-SLR digicams. So, no matter how many megapixels a
point-and-shoot camera’s sensor can hoard, that sensor generally isn’t as big
as a dSLR’s. And when it comes to reducing noise, the size of the sensor is
one of the most important factors.


Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book) Click here to Read more...

Improving Your Photography with a dSLR

The differences between digital SLRs and the camera that you used before you saw the (digital SLR) light depends on where you’re coming from. If your most recent camera was a point-and-shoot digital model, you know the advantages
of being able to review your photos on an LCD screen an instant after you
take them. And, if you’re serious about photography, you also understand the
benefits of fine-tuning your photos in an image editor. If you’re making a longdelayed
switch to a digital SLR from a film SLR, you’re likely a photo enthusiast
already and well aware that a single lens reflex offers you extra control over
framing, using focus creatively, and choosing lenses to produce the best perspective.
And, if you’re making the huge leap from a point-and-shoot non-SLR
film camera to a digital SLR, you’re in for some real revelations.
A digital SLR has (almost) all the good stuff available in a lesser digital
camera, with some significant advantages that enable you to take your photo
endeavors to a new, more glorious level of excellence. Certainly, you can
take close-ups or sports photos by using any good-quality film or digital
camera. Low-light photography, travel pictures, or portraits are all within the capabilities of any camera. But digital SLRs let you capture these kinds of
images more quickly, more flexibly, and with more creativity at your fingertips.
Best of all (at least, for Photoshop slaves), a digital SLR can solve problems
that previously required you to work long hours over a hot keyboard.
Despite the comparisons you can make to other cameras, a digital SLR isn’t
just a simple upgrade from a conventional film camera or another type of
digital camera. A dSLR is very different from a film SLR, even though some
vendors still offer film and dSLRs that look quite a bit alike and share similar
exposure metering, automatic focusing, and other electronics, as well as
interchangeable lenses. If you look closely, you can find that the digital SLR
camera is different than a film SLR, and you use it differently to take pictures.
In the sections that follow, I introduce you to the advanced features and
inner workings of a dSLR so that you can begin getting the most out of your
camera.

 Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

dSLR: dNext Great Digital Camera

Surprise! Digital SLRs are now available in virtually every price range. As
recently as 2003 (the Dark Ages of digital photography), a basic entry-level
dSLR could cost $2,000 or more. At that time, the original Canon Digital Rebel
and Nikon D70 models made it possible for serious photographers to purchase
a real dSLR — with lens — for less than $1,000. A few years later, you
could get similar kits — but with more resolution and improved features —
for $599 or less. Today, you’d have difficulty finding a dSLR that doesn’t have
at least 12 million pixels of image-grabbing sharpness.

So, almost anyone can afford to make the jump to a digital SLR. If you already
have, you’ve discovered that the dSLR lets you take pictures the way they’re
meant to be taken. After they use other film or digital cameras, avid photographers
interested in taking professional-looking photos notice why dSLRs
stand out:

1. You can view a big, bright image that represents (almost) exactly what
you see in the final picture. No peering through a tiny window at a miniature
version of your subject with a tiny optical viewfinder. Digital SLRs
have big and bright viewfinders that show virtually the entire image, so
you don’t have to wonder whether you chopped off the top of someone’s
head. Using the optical viewfinder, which comes as standard equipment on
every dSLR, means that you don’t have to squint to compose your image at
arm’s length on an LCD (liquid crystal display) viewfinder that washes out
in bright sunlight. However, if lighting conditions permit, most digital SLRs
also allow you to preview your picture on the back-panel LCD (just like a
point-and-shoot camera), giving you the best of both viewing worlds.

2. A dSLR responds to an itchy trigger finger almost instantly. Forget
about pressing the shutter release and then waiting a second or two
before the camera decides to snap the shot. Although newer point-andshoot
cameras are more responsive than older versions, few match the
ability of dSLRs to crank out shots as fast as you can press the button.
Even fewer point-and-shoot cameras are capable of the four-to-nineframes-
per-second continuous shooting rates available with some of the
digital SLRs aimed at more advanced photographers.

3. You have the freedom to switch among lenses. For instance, you can
switch among an all-purpose zoom lens, a super-wide-angle lens, an
extra-long telephoto lens, a close-up lens, or other specialized optics
quicker than you can say 170-500mm F/5-6.3 APO Aspherical AutoFocus
Telephoto Zoomexpialidocious. (Best of all, you don’t even have to know
what that tongue-twister of a name means!)
Just be prepared to succumb to lens lust, a strange malady that strikes
all owners of dSLRs sooner or later. Before you know it, you find yourself
convinced that you must have optical goodiesfor taking photos of wildlife
from enough of a distance to
avoid scaring away the timid
creatures. If you’re ready to say sayonara to film, adiós to poorly exposed and poorly composed pictures, and auf Wiedersehen to cameras that have sluggardly performance, it’s time to get started.The sections that follow (as well as other chapters in this part) introduce you to the technical advantages of the digital SLR and how you can use the dSLR features to their fullest. When you’re ready to expand your photographic horizons even further,

 Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...

dSLR camera's lens

The digital single-lens reflex (dSLR) is the great step upward for photographers

who want to expand their creative horizons — or simply just get

better pictures. Whether you want to become a serious photo hobbyist, have

a hankering to turn pro, or want to take advantage of the improved control

that digital SLRs give you over your photography, discovering how to use

this tool of the future should be high on your priorities list.

The latest digital SLRs have features that no one had even dreamed of back

when I wrote the first edition of this book. All the major bugs of the earliest

dSLRs have been magically transformed into killer features in the latest

models. Today, you can preview your images by using Live View features

before you snap the shutter. Dust that collects on the sensor causes much

less of a problem thanks to built-in sensor-cleaning features. You get better

image quality than in earlier models, thanks to higher resolutions (you can

commonly get 15 megapixels and up, even in low-cost dSLRs), super-sensitive

sensors that can capture images in near darkness, and inexpensive but effective

anti-shake technology built into cameras or lenses.

Most recently, the only remaining drawback of digital SLRs — the fact that

you couldn’t shoot movies (long a common feature in point-and-shoot

cameras) — was swept aside with the introduction of new models that grab

HDTV-quality video with sound.

Best of all, all these capabilities are eminently affordable. Digital SLRs in the

$500-to-$1,000 range today can outshoot the $5,000 professional models of

five years ago and are light-years ahead of even the best point-and-shoot

models. The dSLR provides more control over what portions of your image

you want in sharp focus, boasts lower levels of the annoying grain effect

called noise, and operates fast enough to capture the most fleeting action.

If that isn’t enough, you can change lenses, too, adding super-wide perspectives

or the huge magnification possibilities of long, long telephoto lenses to

your repertoire.

Almost all the other advantages of digital photography come with your digital

SLR camera, too. You can review your image immediately, upload the

photo to your computer, make adjustments, and print a sparkling full-color

print within minutes. You never need to buy film. You decide which images

to print and how large to make them. You can proudly display your digital

photographic work framed on your wall or over your fireplace. You can even

make wallet-sized photos, send copies to friends in e-mail, or create an online

gallery that relatives and colleagues can view over the Web.

 Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)

Click here to Read more...