How To Do Everything With Your Digital Cameraby Dave Johnson
Learn to set up and take high-quality photographs with your digital camera. This easy-to-follow guide explains how to enhance and improve existing images as well as print your photos and publish them on the Web for others to see. You'll also get coverage of related equipment including editing software, hardware add-ons, and online image management tools.
Digitize-and realize-your vision! This complete volume will help you get great results from your digital camera. Learn digital photography basics, share results through e-mail or the Internet, electronically store images, apply advanced photography techniques, perform image editing, and more. This book dissects digital photography in bite-sized, understandable sections that will help anyone—from beginner to professional—make the transition to the digital arena. Master image handling and editing tools including scanners, monitors, and software applications. Now, you can tap the mystery of digital image making-and start taking your very best pictures.
*Bring your digital vision to life with powerful digital tools *Organize, edit, and store your favorite photos in digital media *Print your own pictures, e-mail them to friends and family, or display them on the Internet for everyone to enjoy *Master companion hardware like storage cards, scanners, and color printers *Upload pictures directly from your camera to your own Web site, or post them to a gallery site *Explore advanced digital photography techniques like night, action, and slow-motion photography *Troubleshoot and care for your digital camera *Access online and offline resources to help you pick the best digital camera, and make hardware choices
Read an Excerpt
· Tell the difference between analog and digital camera operation
· Distinguish between slide and negative photography
· Pick ISO settings for a digital and film camera
· Match aperture and shutter speed settings for correct exposure
· Use the Sunny 16 Rule
· Modify the Sunny 16 Rule based on ISO and lighting conditions
· Adjust exposure manually
· Tweak exposure with your camera's EV settings
· Choose metering modes for better pictures
· Use exposure lock to optimize exposure
· Tell when to ignore the camera and make your own exposure decisions
Some people think that photography is akin to magic. They turn on the camera, snap a picture, and a day or two later they've got a mystical re-creation of the scene they saw in the viewfinder. With a digicam, it's even more magical-the pictures are available instantly! How does it work? Who knows?
The problem with the Abe Simpson approach to photography (which I've so named based on an episode of The Simpsons in which someone took a picture of old Abe and he shouted feebly, "You stole my soul!") is that you can never really improve if you don't know what your camera does or why-and if you don't know how you can influence the camera yourself to improve your shots. This chapter, consequently, walks you through the exposure process. Here you'll learn what constitutes a proper exposure and how to get it yourself-even on cameras that are mostly automatic.(1)How Cameras Take Pictures
The best place to start is often right at the beginning-how on earth does a camera take a picture, anyway?
All cameras, regardless of type, work more or less the same way - as depicted in the illustration below. They open their shutter for a brief time, allowing light to enter. That light then interacts with a sensitive photo-receptor (like film, or perhaps a computer chip), and an image is recorded. Let's start by looking at a traditional 35mm camera to give us a little perspective.
(2)Inside a 35mm Camera
Traditional cameras rely on good old-fashioned film. But what is film, really? It's just a strip of plastic that has been coated with a light-sensitive chemical. The chemical soup on the film is loaded with grains of silver halide. When exposed to light, the silver halide reacts, and that is the essence of photography. The longer the film is exposed to light, the more the silver is affected.
There are two kinds of film in common use today: negative and slide film. They work a little differently, but the end result is similar. When you use color negative film, also referred to as reversal film, the film itself becomes a "negative" image of the scene you photographed. After processing-which includes letting the film sit in a chemical bath that coaxes the grains of silver to visually materialize on the film-the negative is used to create positive prints of the scene. It's a two-step process, and one that is highly subjective. When creating prints from negatives, photo-finishers often tweak the picture to improve its appearance. Of course, what the corner shop considers an "improvement" may not be what you were trying to achieve, and that explains why your pictures never seem to benefit from filters, exposure changes, or any of the other corrections you try to make when taking pictures.
But I digress. The other kind of film is simple slide film. This is a color positive development process-after fixing the slide film in its chemical bath, the film becomes slides that can be held up to the light to display images.
No matter what kind of film you have, it eventually needs to be exposed to light. When you take a picture, you obviously press the shutter release. The shutter release instructs the camera to open a diaphragm in the lens for a brief period of time and then close again. If all went well, that was just long enough to properly expose the film.
(s)The Moment of Exposure
Depending upon the kind of camera, the events at the moment of exposure can be quite complicated. In a modern 35mm SLR, for instance, microprocessor-controlled sensors determine the exact amount of light needed to expose a picture at the moment you press the shutter release. The lens automatically adjusts the size of its opening to admit the correct amount of light, the mirror mechanism that usually lets you look through the viewfinder flips up and out of the way, and the aperture opens for the programmed amount of time. Point and shoot cameras, in contrast, don't use mirror mechanisms to let you see through the lens before the shot, so there are fewer moving parts at the moment of exposure. Tip: If you want to shoot with 35mm film, scan the results, and then edit and print the results on your PC, you might want to work with slide film. Slides are more exacting-they require you to nail the exposure fairly precisely, as I explain in Chapter 11-but they'll better represent what you actually photographed instead of the local photo shop's vision of what you photographed.
(3)How and Why Film Varies
As you no doubt know by shopping for film, not all canisters of 35mm film are alike. Film is differentiated principally by its speed, or ISO number.
A film's ISO number refers to how sensitive it is to light. The lower the number is, the less sensitive-requiring long exposures or very bright scenes.
Note: ISO stands for International Organization for Standardization, and that's the group that helped establish how the number scheme works. Film around the world uses ISO numbers, so you can buy it anywhere, and it'll all work the same. In the United States, photographers used to call this system ASA, which stood for the American Standards Association. That term was essentially abandoned about 20 years ago, so if you want to be considered a gristled old geezer, you can refer to ISO numbers as "ASA."
A fairly typical ISO number for ordinary daylight photography is ISO 100. Increasing the ISO to 200 doubles the sensitivity of the film; dropping back to an ISO of 50 halves the sensitivity of the film.
This has a tangible effect on the mechanics of photography. To see why, look at Figure 2-1. This diagram shows a typical camera body as a picture is taken. The lens is equipped with a diaphragm-called an aperture-that has a certain diameter and consequently is designed to allow a specific amount of light through to the film. With ISO 100 film in specific lighting conditions (say, at midday) the shutter might need to open for a 250th of a second (1/250) to adequately expose the picture.
Figure 1: Every camera-no matter what it uses for film-controls light with some sort of aperture.
But what happens if we instead try to take the same picture with ISO 200 film? The film is exactly twice as sensitive to light as the previous roll of film. And that means, all other things being equal, that we only need to leave the shutter open for half as long (a 500th of a second, or 1/500) to take the same picture.
That's not all. Suppose you're trying to take a picture in late afternoon-when there isn't as much light available? You might need to leave the shutter open for 1/30 in that situation to gather enough light. That shutter speed is a bit on the slow side, though. Not only might you jiggle the camera as you're taking the picture (it's hard to hold a camera steady for 1/30), but your subject might move as well, causing a blurry picture. You can probably guess what the solution is-stepping up to ISO 200 film will enable you to grab that picture at a much more reasonable 1/60, and ISO 400 would halve the shutter speed yet again, to a crisp 1/250.
(3)The F/stop Ballet
So far so good-but there's one other aspect to consider, and that's the fact that camera lenses can change the diameter of their aperture, thus letting in more or less light as needed.
The size of a camera's aperture at any given moment is called the f/stop, or sometimes referred to as the f number of the lens. F/stops are represented by numbers that start with "f/"-like f/2, f/5.6, and f/11. The larger the number, the smaller the opening, so an f22 is very, very small (not much light gets through to the film), while a lens set to f/1.2 is a huge opening that literally floods the film with light. Every "whole" f/stop, such as from f/5.6 to f/8 or f/11 to f/16, increases or reduces the light by 100%. If you adjust a lens from f/8 to f/11, for instance, you've reduced the light by half. We'll talk about this in more detail in Chapter 3 (it's really important, yet really simple), but for the moment take a look at Figure 2-2. This diagram shows the relationship between f/stop and shutter speed. As you reduce the shutter speed, you need to increase the diameter of the aperture in order to have enough light to take a properly exposed picture. Figure 2: There's a relationship between a camera's shutter speed and aperture setting. callouts
Of course, there's a link between aperture, shutter speed, and your film's ISO rating. Look at Figure 2-3. At a given film speed, you can take a picture with a specific aperture/shutter combination. If you double the film speed without changing the lighting conditions, though, you have to adjust the aperture and shutter speed so that you still get a properly exposed picture. And perhaps most importantly for us, suppose you are in the situation described here:
Figure 3: Film speed-known as ISO-also affects shutter speed and aperture. callouts
You want to take a picture of frolicking lions at the zoo near dusk. The aperture is wide open at f/2-it won't open any farther. Nonetheless, your camera needs to use the relatively slow shutter speed of 1/15 second to take the shot. You know the image would be a blurry mess at that sluggish shutter speed, so what is there to do? Take a look at your film speed. It's ISO 100 film. Well, you might be in luck. If you're willing to pop the film out of your camera and put in film that's two f/stops (often, just called "stops") faster, you can keep the aperture at f/2 and change the shutter speed to 1/60. That's probably good enough to get the shot. Just do it quickly-it isn't getting any brighter out, and if you dally, you might find you need to increase the speed by three stops by the time you get the film loaded and ready to go.
Note: You probably don't need to know this, but it might come in handy during a trivia game some day. Mathematically, f/stops are the ratio of the focal length of the lens divided by the diameter of the opening of the diaphragm. Thus, when you divide the focal length of the lens by a very small opening, you get a large number, while dividing the focal length by a comparatively large diameter gives you a smaller number.
Meet the Author
Dave Johnson is an accomplished photographer in both analog and digital mediums, as well as an amateur musician and music fanatic. As Senior Editor at Planet IT, Dave covers topics like handheld computing, portables, wireless, and imaging technologies. Dave has written for magazines like Home Office Computing, Windows Magazine, Family PC, and Digital Camera, and his 14 books include How To Use Digital Video and the best-selling How to Do Everything with Your Palm Handheld (nearly 35,000 copies sold).
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I would describe myself as an amateur photographer striving for professional results. The digital camera software I use happens to be Corel's Photo Album 6and Paint Shop Pro XI. A demonstration version came with my new computer so that's how I got hooked. Dave Johnson, the aurhor, comments in the book's introduction:'While the techniques I describe in this book are all done with Corel's Paint Shop Pro, you don't have to be a Paint Shop Pro user to get the most out of it' If you happen to be a Corel photo software user like me, this book fuctions like a third party manual helping users navigate the various menus and get the most out of their software. Thanks to this book I am getting professional results. I owe my progress to date to this book and recommend it highly to others.