- Tìm hi u v Digital Photography – Bài th 2
( ti p theo kỳ trư c)
Dư i ây là bài h c ng n v digital photography góp nh t t
Internet- Bài này ư c tác gi là giáo sư nhi p nh Dennis Curtin cho
phép ăng l i dùng vào m c ích giáo d c. M i kỳ báo s có m t
chương ng n v tài digital chúng ta cùng h c thêm. Tuy nhiên
chúng ta nên nh r ng : Ki n th c căn b n c n ư c trau d i trư c ã, và
t nh ng bài h c căn b n nhi p nh c a các máy ch p phim và khía c nh
ngh thu t lãnh h i qua các l p h c căn b n. Ta s sáng t o ra nhi u hình
nh giá tr , dùng b t c phương th c nào cũng ư c. Xin các b n ch u
khó c bài này b ng ti ng Anh nguyên b n.
Free photography, photographic freedom
Although it's both the immediacy and flexibility of digital
photography that has made it so popular, there is one aspect that is rarely
mentioned. This is the new freedom it gives you to explore creative
- photography. In the 1870's when William Henry Jackson was carrying 20
x 24 glass plate negatives around the West on a mule, you can bet he
hesitated before he took a photograph. We may not be carrying window-
sized glass plates, but you and I also hesitate before taking a picture.
We're always doing a mental calculation "is it worth it?" Subconsciously
we're running down a checklist of costs, times, effort, and so on. During
that "decisive moment," the image is often lost or we fail to try new
things. We lose the opportunity for creative growth and choose to stay
with the familiar that has delivered for us in the past. Surprisingly,
Jackson had one big advantage we've lost over the last century. If an
image didn't turn out, or if he was out of glass plates, he could just scrape
the emulsion off a previously exposed negative, recoat the plate, and try
again. Digital photography not only eliminates that nagging "is it worth
it?" question, it also returns us to that era of endlessly reusable film (and
we don't need a mule to carry it). Hand the camera to the kids, take weird
and unusual angles, shoot without looking through the viewfinder, and
ignore all previously held conceptions about how to take photographs.
You may be surprised at the photos you get if you exploit this new era of
- The three steps of digital photography
Digital cameras are just one link in a long chain leading from the
original scene through to the final image that you display or distribute. In
fact, a digital camera isn't even an absolutely necessary link in the chain.
The key element in digital photography is an image in a digital format
made up pixels. Although a digital camera captures photos in this digital
format, you can also scan slides, negatives, or prints to convert these
traditional images into the same digital format.
To understand how the camera fits in with other parts of the digital
photography system, it helps to understand the three basic steps involved
in creating and using digital photographs-input, processing, and output.
Step 1. Inputting photographs
Input devices get photographs or other data into a computer system.
The input device you're probably most familiar with is the keyboard.
However, there are hundreds of other input devices including mice, touch
pads, voice recognition systems, scanners, and so on. Here are some of
the input devices you can use to create digital photographs:
- Digital still cameras capture photographs in a digital format.
Film cameras capture photographs on slides, negatives, or prints
which you can then scan to convert them to digital photographs.
Video cameras capture images in a video format. You can then use
a frame grabber to isolate out individual frames and save them as still
Digital video cameras sometimes are able to capture still images
just like a digital still. You can also use a video-editing card to extract
still images from the digital video.
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. The things you can do to a digital image are almost endless.
In some cases you improve an image by eliminating or reducing its flaws.
In other cases, you adjust an image for other purposes, perhaps to make it
smaller for e-mailing or posting on a Web site. Finally, you might take an
- image to a new place, making it something it never was. Here are just a
few of the ways you can process images:
Crop the photograph to emphasize the key part.
Reduce the number of pixels in an image to make it smaller for
posting on the Web or e-mailing.
Use filters to sharpen it or even make it look like a watercolor or
Stitch together multiple frames to create panoramas.
Merge two images to create a 3D stereo effect, or an animated
image for display on the Web.
Change brightness and contrast to improve the image.
Cut and paste parts of one image into another to create a photo
Convert the photograph to another format.
Step 3. Outputting photographs
- Once an image is the way you want it, you can output it to share
with others. There are lots of ways to display and distribute digital
photographs. Here are some of the most popular ways:
Print the image on a color printer or send it to an on-line service to
print it on silver-based paper just like that used with film cameras.
Insert the photograph into a word processing or desktop publishing
Post the photograph on a Web site or a photo network.
E-mail the photograph to friends or family members.
Send the photo to a service on the Web for specialty printing onto
T-shirts, posters, key rings, mouse pads, even cakes and cookies.
Store the photograph on your system for later use.
Use a film recorder to convert the photograph into a slide that you
can project with a slide projector.