Choose Your Weapons

Narrowing down your choices to a specific camera category is only half the job. Because features can vary widely even within a category, you'll still need to decide which capabilities are "must haves" and which are "nice to haves if they don't cost an arm and a leg." This section will outline your chief options among lens requirements, resolution, storage options, exposure controls, and viewfinders.

Understanding Lens Requirements

The lens is the eye of your camera. It captures and focuses the light from your scene onto your sensor. Your digital camera's lens affects the quality of your images as well as the kinds of pictures you can take. What really counts is the quality of the lens, the amount of light it can transmit, its focusing range (how close you can be to your subject), and the amount of magnification (or zooming) that the lens provides. Here are some of the things you should consider.

Lens Aperture

The lens aperture is the size of the opening that admits light to the sensor, relative to the magnification or focal length of the lens. A wider aperture lets in more light, allowing you to take pictures in dimmer light. A narrower aperture limits the amount of light that can reach your sensor, which may be useful in very bright light. A good lens will have an ample range of lens openings (called "f-stops") to allow for many different picture-taking situations.

F-stops are actually the denominators of fractions rather than actual measurements, so an f2 opening is larger than an f4 opening, which is in turn larger than an f8 aperture, just as 1/2 is larger than 1/4, which is larger than 1/8. Each stop you open up (going from, say f8 to f5.6) doubles the amount of light reaching the sensor.

You generally don't need to bother with f-stops when taking pictures in automatic mode, but we'll get into apertures from time to time in this book. For now, all you need to know is that for digital photography, a lens with a maximum (largest) aperture of f2.8 is "fast," while a lens with a maximum aperture of F8 is "slow." If you take many pictures in dim light, you'll want a camera that has a "fast" lens. The sensitivity of the sensor, discussed later, is also important for low-light pictures.

Digital camera lenses tend to be slower than their prime lens (non-zooming) counterparts. That's because digital optics are almost always zoom lenses, and zoom lenses tend to have smaller maximum apertures at a given focal length than a prime lens. For example, a 28mm non-zoom lens for a 35mm camera might have an f2 or f1.4 maximum aperture. Your digital camera's zoom lens will probably admit only the equivalent of f2.8 to f3.5 when set for the comparable wide-angle field of view. The shorter actual focal length of digital camera lenses also makes it difficult to produce effectively large maximum apertures.

What about the minimum aperture? The smallest aperture determines how much light you can block from the sensor, which comes into play when photographing under very bright lighting conditions (such as at the beach or in snow). Digital cameras don't have as much flexibility in minimum aperture as film cameras, partly because of lens design considerations and partly because the ISO 100 speed of most sensors is slow enough that apertures smaller than f5.6 or f8 rarely are needed. A digital camera's shutter can generally reduce the amount of exposure enough that resorting to the f11, f16, or f22 minimum apertures found on film cameras isn't necessary. (If you're using a digital SLR that uses the same lenses as a film camera, you'll of course have access to these smaller apertures.)

Seasoned photographers will know that a second reason for using a smaller lens aperture is to increase depth-of-field. The smaller the lens opening, the more depth-of-field that is available. In practice, a phenomenon known as diffraction reduces the effective sharpness of lenses at smaller apertures. A particular lens set at f22 may offer significantly less overall resolution than the same lens set at f5.6, even though that sharpness is spread over a larger area. Depth-of-field is also tied to the absolute focal length of the lens, too, though, so digital cameras with those 7mm to 35mm zoom lenses already have enough depth-of-field, even at maximum aperture, that stopping down provides no additional benefit. So, unless you're using a digital SLR that accepts conventional lenses, the minimum aperture available isn't particularly important.

Manual Exposure Adjustments

Digital camera lenses that have a selection of f-stops adjust themselves for the proper exposure automatically. The only exceptions are the least expensive models with lenses that cannot be adjusted for exposure at all. Serious photo-hobbyists and professionals might also want the option found in higher-end cameras of setting the lens f-stop manually to provide special effects or more precise exposure. These controls come in several forms, and I'll discuss them in the exposure control section later in this chapter.

Zoom Lens

A zoom lens is a convenience for enlarging or reducing an image without the need to get closer or farther away. You'll find it an especially useful tool for sports and scenic photography or other situations where your movement is restricted. Only the least expensive digital cameras lack a zoom lens. Some offer only small enlargement ratios, such as 2:1 or 3:1, in which zooming in closer produces an image that is twice or three times as big as one produced when the camera is zoomed out. More expensive cameras have longer zoom ranges, from 4:1 to 10:1 and beyond.

In addition, there are two ways to zoom a lens. With so-called optical zoom, the relationships of the individual elements of the lens are changed to produce the changes in magnification. Because the lens elements can be fine-tuned, this produces the sharpest image at each lens magnification. For example, a typical zoom might be described as having 10 elements in eight groups. Each of the groups can be moved individually to provide the desired magnification and the best image. The optical science behind these relationships is complex, and we should be thankful that our spanking new digital cameras have 50 years or more of research backing the optical component.

Digital cameras also feature digital zoom, in which the apparent magnification is actually produced by simply enlarging part of the center of the image. Your camera's viewfinder will probably have a frame or other indicator that shows just what portion of the viewed image will be magnified to simulate the zoom setting. Digital zoom is less sharp than optical zoom. Indeed, you can often do a better job by simply taking the picture at your camera's maximum optical zoom setting and enlarging the image in your image editor.

That's all you really must know about zoom lenses. However, here's a bit more detail for the technically inclined. It's easiest to think of zoom ranges in terms of magnification, but the magnification of an image is actually measured in something called focal length. Focal length is a ratio between the size of the film or sensor image and the distance from a position in the lens to the plane of the film or sensor. Focal length is used to measure whether a lens provides a wide-angle, normal, or telephoto view with a particular size sensor or film.

So, a 6.5mm focal length lens or zoom setting would provide a wide-angle picture with a .5 inch sensor, while a 12mm focal length lens or zoom setting would provide a telephoto effect. Camera vendors often express the focal length of digital camera lenses in terms of how they are equivalent to the common lenses used with 35 mm cameras. They do this because most camera buffs already know that a 28mm lens is a wide-angle optic on a 35mm camera, a 50mm lens is a "normal" lens, and a 135mm lens is a particular kind of telephoto. Digital camera sensor size can vary from model to model, so the actual focal length of a digital camera lens means a lot less than its 35mm "equivalent."

That Crop Factor

With digital SLR cameras, the situation becomes a little more complex, because the lenses used actually are, in many cases, designed for 35mm film cameras. Although dSLR sensors are larger than those found in non-SLR digital cameras, they are still, by and large, smaller than a full 35mm film frame. (Although some digital SLRs do use full-frame sensors.) That means it's necessary to use a crop factor (sometimes called a lens multiplier) to calculate the effective focal length of a lens. Common crop factors are 1.3X, 1.5X, and 1.6X. Mount a 100mm lens on one of these cameras and your field of view will be equivalent to 130mm, 150mm, or 160mm respectively—even though the range of sharp focus (or depth-of-field) remains the same as what you'd expect with a 100mm lens.

While the crop factor increases the telephoto reach of a lens, as shown in Figure 2.20, it also reduces the perspective of wide-angle lenses. Your 18mm super-wide lens becomes an ordinary 29mm wide angle when mounted on a camera with a 1.6X crop factor. To gain true wide-angle coverage, digital SLR owners often have to purchase new, expensive lenses.

Figure 2.20. A 50mm lens on a full-frame camera produces the view at left. On a dSLR with a 1.5X crop factor, the view looks more like that of a short telephoto lens.

Because the elements of a lens are moving around in strange and mysterious ways, the effective aperture and focus of a lens may vary as the magnification settings change. A lens that has an f2.8 maximum aperture at its wide-angle setting may provide only the amount of light admitted by an f3.5 lens at the tele position. Focus can change, too, so when you focus at, say, the wide-angle position and then zoom in to a telephoto view, the original subject might not technically still be in sharpest focus (although the huge amount of depth-of-field provided by digital camera lenses might make the difference impossible to detect). You'd notice the differences only when using the camera in manual exposure or focusing mode, anyway. When set to autofocus and autoexposure, your camera will provide the optimum setting regardless of zoom magnification.

Focus Range

The ability to focus close is an important feature for many digital camera owners. One of the basic rules of photography is to get as close as possible and crop out extraneous material. That's particularly important with digital cameras, because any wasted subject area translates into fewer pixels available when you start cropping and enlarging your image. So, if you like taking pictures of flowers or insects, plan to photograph your collection of Lladró porcelain on a tabletop, or just want some cool pictures of your model airplane or stamp collections, you'll want to be able to focus up close and personal.

What's considered close can vary from model to model; anything from 12 inches to less than an inch can be considered "close-up," depending on the vendor. Fortunately, those short focal length lenses found on digital cameras come to the rescue again. Close focusing is achieved by moving the lens farther away from the sensor (or film) and a 7.5mm lens doesn't have to be moved very far to produce an image of a tiny object that fills the viewfinder.

The closer you get, the more important an easily viewed LCD display (that screen on the back of your camera) becomes. You'll also want automatic focusing. Lower-cost cameras with non-zooming lenses may not have focusing abilities at all; they provide sufficiently sharp focus at normal shooting distances (a few feet and farther) and, possibly, at a particular close-up distance (typically 18 to 24 inches). More expensive cameras have automatic focus that adjusts for the best setting at any distance. Higher-end cameras might also have manual focusing that can let you "zero" in on a portion of your image by making everything else seem blurry. Figure 2.21 shows an extreme close-up photo.

Figure 2.21. Get as close as you like with a digital camera that has macro capabilities.

Add-on Attachments

Photographers have been hanging stuff on the front of their lenses to create special effects for a hundred years or more. These include filters to correct colors or provide odd looks, diffraction gratings and prisms to split an image into pieces, pieces of glass with Vaseline smeared on them to provide a soft-focus effect, and dozens of other devices. These range from close-up lenses to microscope attachments, to infrared filters that let you take pictures beyond the visible spectrum. Add-on wide-angle and telephoto attachments are also available, along with slide copy accessories and other goodies. If you're serious about photography, you'll want to explore these options.

Make sure your camera's lens has a standard screw thread size (usually from 28mm to 55mm or larger) so you can use standard accessories. Some cameras require special attachments for the front of the lens, which may lock you into accessories from that particular vendor. Fortunately, enterprising third-parties are quick to create adapters that work with the most popular digital models. A few notorious models have lens elements that move forward through what would be the front of the lens, making attachment of any sort of filter rather difficult. Check out your intended camera model carefully before buying.

The Myth of Resolution

True or false: You can never be too rich, too thin, or have too much resolution in your digital camera.

Bill Gates and most fashion models would probably agree with the first two points, but the third assertion is open for discussion, even though most buyers of digital cameras seem obsessed with the number of pixels they can capture. Can you actually have too much resolution?

I'd amend the statement to say something along the lines of, "buy and use as much actual resolution as you really need for your photography, unless the extra pixels won't cost you much." The salient points are that, first, you don't need to pay a huge extra amount for resolution that you won't really use, and, second, resolution overkill can actually hamper your creativity and provide a productivity bottleneck. Someone who could get along just fine with a medium resolution $400 camera would be crazy to pay $1,000 or more for a much higher-resolution model if they won't be using that resolution now. After all, next year, when they might actually need that much pixel-grabbing power, cameras that offer that much resolution will probably cost only $400. In this case, waiting until you really need the resolution would save $200, and you'd end up with two usable cameras!

Even if the pixels are available, you shouldn't always use every last bit of resolution in any case. Consider these examples:

• Most of your photos are posted on the web in sizes that rarely exceed 600 x 400 pixels. You often crop your photos, and want to start with a nice, sharp original before reducing it to the size you'll display on your web page. A 4- or 5-megapixel camera will do a great job and provide enough resolution for general photography and reasonably sized prints.
• You love sports photography. A digital camera with 6 megapixels will certainly let you grab some great sports shots, and even give you enough resolution that you can enlarge portions of the image to simulate having a longer telephoto lens than you really have. Yet, it's not always a good idea to take sports pictures at the max res setting. When action is fast moving, you may lose some great shots while you wait for a high-resolution photo to be stored so you can take the next one. That's why cameras like the Nikon D2X actually use lower resolution (cropping the image from 12.4 megapixels to 6.8) for its fastest 8 frames-per-second continuous shooting rate. In addition, the amount of buffer memory built into your camera can be crucial. Some 6-megapixel cameras can take only one or two pictures at a time. Others can fire off a half dozen or more before the buffer fills up. When rapid fire or photo sequences are important, you may get better overall pictures by dialing back to a lower resolution if you gain the ability to shoot faster and smarter.
• You're documenting your vacation, and want to snap off 100 photos a day. You don't have access to a laptop, nor any other means of emptying your digital film cards on a regular basis. If you want to shoot everything using your camera's top resolution using the RAW file format (more on that later in this book), you'd better count on having one 1GB memory card for each day of your trip. Of course, you can review your photos as you take them, or at the end of the day, and delete the real clunkers. But even so, your costs for digital "film" can really add up, and you really only need that much storage once or twice a year. Who says digital cameras are cheaper to operate than film cameras? The answer may be to shoot tighter and scale back the resolution of most of your shots to a smaller size or use a higher compression ratio that costs you a bit of sharpness. Can you really see the difference in a 5 x 7 print of you standing atop Mount Everest taken at the 8-megapixel setting from one taken at 6 megapixels?

Keep in mind that resolution is largely a myth, anyway. Pictures taken with a highquality 6-megapixel camera can easily look better and sharper than those grabbed with a model touting 8 megapixels of resolution. How so? Consider all these factors that can affect the quality of the finished image.

• True resolution. As mentioned earlier in this chapter, your 6-megapixel camera isn't really capturing 6 million pixels of information in the first place. If it uses a Bayer matrix sensor, it's grabbing a maximum of 50 percent of the green pixels, and a maximum of 25 percent of the red and blue pixels. The other pixels are created through interpolation, a scheme that has a high degree of accuracy (because adjacent pixels are a very good indicator of what a particular pixel should be), but is far from perfect.
• Shutter speed/camera motion/subject motion. Your subject might be moving. The photographer might not know how to hold a camera steady and might be a little jittery. You may be taking a picture at a long telephoto setting, which automatically magnifies camera or subject motion. The camera's shutter speed may be too slow to freeze the subject while all this movement is going on. As a result, a "high-resolution" photo may be less sharp than one taken at a lower resolution at a higher shutter speed, with a steadier photographic hand or an unmoving subject. Something as simple as a tripod might magically transform your medium-resolution camera into one that can thoroughly thrash the results of a handheld high-res model.
• Lighting/contrast. An image of a higher-contrast subject, or one taken with higher-contrast lighting, can look sharper than a low-contrast picture of similar subject matter.
• Focus. A sensor can only capture a sharp image if it's sharply focused. A poor autofocus system or inept use of manual focus can reduce the sharpness of even the highest-resolution image.
• Optics. Even the highest-resolution sensor will be only as good as the lens used to capture the image. Fortunately, lenses designed for digital cameras are capable of producing many times the resolution that a typical sensor can resolve, so a stellar optic doesn't necessarily have much of an advantage over a poor one from a resolution standpoint. However, lenses, particularly zoom lenses, can have other problems. Perhaps you've left a big thumbprint on the front of the lens. Maybe you neglected to use a lens hood, or the lens hood is poorly designed, so extraneous light enters the optical system and reduces contrast and detail. A really cheap lens might not focus all three colors of light at the same point, producing color fringing. A poor lens or one badly used can reduce the final resolution of an image far more than the lack of a few million pixels.

Image resolution (the number of picture elements, or pixels your camera can capture) can determine (along with the quality of your lens and sensor) how sharp your images will be. Resolution is measured by the number of pixels wide by the number of pixels high that can be captured by your camera's sensor. The number may not be strictly true, as some cameras "manufacture" pixels by a mathematical process called interpolation, but it generally provides a good measure of a camera's relative sharpness. You can establish how much resolution you require by estimating how many of your photos will fall into one of these categories:

• Low-resolution requirements: Most pictures for web pages or online auctions; photos that won't be cropped very much; pictures that won't be printed in large sizes. If all your photos are of this type, you'll probably be able to get away with a camera with as little as 1600 x 1200 pixel resolution. In the long run, though, if you're serious about photography, you'll probably want a camera with a little more resolution muscle.
• Medium-resolution requirements: If you often need to trim out unwanted portions of your pictures or will be making somewhat larger prints, you'll need a higher-resolution camera with resolution of 2048 x 1536 pixels as a bare minimum.
• High-resolution requirements: If you like to do lots of cropping or make prints that are 5 x 7 to 8 x 10 inches or larger, you'll need a high-resolution camera. Today, these are considered models with 6 to 14 megapixels or more. In the future, you can expect the number of pixels to increase and the prices to come down, so that even the highest-resolution models will be easily affordable by serious digital photographers.

You'll probably want a choice of resolutions within a given camera, so you can select the best resolution for the job at hand. For example, if you're shooting a large batch of pictures for a web page or online auction, you'll want to have a relatively low resolution, so you can take more pictures, more quickly, with a minimum amount of resizing required in your image editor. You'll also want to be able to quickly switch to maximum resolution to snap a picture you know you'll want to print out.

Your camera's storage format options can also have a bearing on sharpness. Digital cameras usually store photos in a compressed, space-saving format known as JPEG (Joint Photographic Experts Group). JPEG format achieves smaller file sizes by discarding some information that may not be needed in most cases. The JPEG format has various "quality" levels. If sharpness is very important to you, look for a camera that lets you choose the highest quality JPEG mode when you need it, or which has an optional mode for storing in a higher-quality format such as TIFF (Tagged Image File Format).

One of the first things you'll want to do when you get a new digital camera is set it up on a tripod and take a series of pictures at your camera's Standard, Fine, SuperFine, Ultrafine, and TIFF modes. Then compare the shots to see just how big the difference is. With several cameras that I use, it's difficult to see any difference between the default Fine setting, which yields relatively compact 3MB image files, and its RAW mode, which creates files that are at least twice as large. We'll look at file formats in a little more detail in Chapter 4.

Storage Options

Few people select a digital camera based on the kind of storage it provides and, in any case, your storage is usually very open-ended. Virtually all digital cameras have removable storage of some type. Those that don't make you connect your camera to your computer from time to time to download existing pictures to make room for more. In most cases, however, if you need to take more pictures in a session, just buy an additional digital "film" card (usually called CompactFlash, Secure Digital, xD, Sony Memory Stick, or some other trade name). It's unfortunate that vendors seem so intent on introducing more and more memory card formats, because that makes it difficult to swap cards among different cameras and devices.

There are even differences between media that are otherwise compatible. For example, CompactFlash cards come in both Type I and Type II varieties. The chief difference between them is that Type I cards are 3.3mm thick, whereas Type II cards are 5.5mm thick (and thus can have higher capacities). Hitachi's Microdrives are actually miniature hard disks in a CompactFlash Type II configuration. Not all digital cameras can accept both Type I and Type II cards, and not all that are compatible with Type II memory cards work with the more power-hungry Hitachi Microdrives.

Today, CompactFlash and SD Cards are the most common memory devices in use. CompactFlash has been vying for the capacity championship, with cards holding 4 to 8GB. Secure Digital Card (SD Card) and the similar MultiMediaCard (MMC) formats are making some in-roads. (You can use a MultiMediaCard in a camera that accepts SD Card memory; the camera will write more quickly to the SD Card.) There is even a miniSD card, about two-thirds the size of a regular SD Card. Some Fujifilm and Olympus cameras use the tiny xD-Picture Card. If you were hoping that camera makers would standardize on a single digital film format, we're definitely moving in the wrong direction! The good news is that as formats proliferate, the prices for digital memory cards have plummeted.

Some kinds of memory cards claim to have faster writing speeds than others, even within the same format. I've never found the speed of my digital film to be much of a constraint, but if you shoot many action photos, sequences, or high-resolution (TIFF or RAW) pictures, you might want to compare write speeds before you buy. A card that's been tested to write more quickly can come in handy when you don't have time to wait for your photos to be written from your camera's buffer to the memory card. You can read about card speeds at Rob Galbraith's web site at www.robgalbraith.com.

Exposure Controls

Although I mentioned exposure controls under the lens section earlier, exposure involves more than lens settings, of course. Exposure is also determined by the amount of time the sensor is exposed to light (the equivalent of a film camera's shutter speed) and the intensity of the light (which can vary greatly when you're using an external source, such as an electronic flash unit). Digital cameras all have automatic exposure features for both flash and non-flash photography, but some are more flexible than others. Here are some of the options to look for:

• Programmed exposure. Digital cameras take advantage of their computer technology by offering a variety of programmed exposure modes. In addition to standard automatic exposures, you'll find program modes especially for action pictures, scenics, night photography, portraits, or other common types of situations. These modes take into account the need for specific ranges of shutter speeds (as with sports pictures) or exposure weightings (described next).
• Exposure weightings. A sophisticated digital camera doesn't simply look at how much light is passing through the lens to calculate correct exposure. Instead, the viewing area is divided into segments and individual segments can be given greater or lesser weight, depending on the shooting situation. For example, readings may be center-weighted, on the assumption that the most important subject matter will be in the center of the frame. Or, exposures can be calculated from a spot reading of a very small section of the frame. Averaged readings may work best for evenly illuminated scenes. I'll explain about various exposure modes in the next chapter.
• Plus/Minus or Over/Under exposure controls. With these, you can dial in a little more or a little less exposure than the amount determined by your camera's built-in light measuring device.
• Aperture-preferred/Shutter-preferred exposure. With this option, you can set the lens opening you prefer and the camera will choose the correct shutter speed. Or, you can select the shutter speed you want, and the camera will choose an appropriate lens opening. As you'll learn later in this book, these controls can be used effectively to ensure that the camera will select the aperture/shutter speed combination that works best in low light or, perhaps, to stop action.
• Full manual control. With this option, you can set any shutter speed or aperture combination you like, giving you complete control over the exposure of your photo. There are many times when you don't want what the camera considers to be "perfect" exposure. Manual control lets you shoot photos that are "too dark" or "too light" but have the artistic appearance you want.

With these features in mind, ask yourself the following questions:

Can your digital camera take low-light pictures without flash?

Low-light pictures call for an extra-sensitive sensor. Camera specs often provide the equivalents to conventional film speeds, measured in ISO (International Standards Organization) ratings such as ISO 100, ISO 200, and ISO 400. The higher the number, the more sensitive the sensor. Many cameras let you vary the ISO rating, making your camera more "sensitive" under particular situations. Later in this book I'll show you why changing the sensitivity setting is sometimes a good idea, and why it is sometimes not a good idea. As you select a camera, however, look for the stated ISO rating, and see if it can be changed by the user.

Can your camera compensate for backlit or frontlit pictures?

Intermediate and advanced cameras may have a simple provision for departing from the "best" exposure determined by the camera's sensor. For example, you might want to adjust the exposure to compensate for subjects that are strongly backlit (that is, an unimportant background is very bright in comparison to your subject matter) or frontlit (the background is very dark), so the exposure is determined by your actual subject, rather than an overall average of the scene. I'll provide some examples of backlit and frontlit pictures later in the book.

Does your camera have various exposure modes fine-tuned for particular kinds of picture-taking sessions, such as sports, portrait, and landscape photography?

If so, you can dial in one of these and improve the quality of your pictures effortlessly.

How is the light measured?

As I mentioned earlier, digital cameras may have a particular way of measuring light, or may offer several different light-measuring schemes that you can select. For example, your camera may have a "spot" meter that zeroes in on a particular, small area of the image and determines the exposure from that, ignoring the rest of the picture. This feature can be handy when you take many pictures in difficult lighting conditions and would like to specify which area of the picture is used to determine exposure. Or, a camera might measure corners or other specific areas of an image. For the most flexibility, you'll want a camera with several different exposure modes. I'll show you how to use these later in the book.

Can exposure be set manually?

I mentioned earlier that cameras that allow manual setting of the lens f-stop might also let you choose either shutter priority or aperture priority (you set one, the camera sets the other) or full manual control over both aperture and shutter speed.

How flexible are the flash features?

Some cameras might have a fixed flash range so that you are limited to shooting only in the range between 2 and 12 feet from your subject. Others have special settings for telephoto pictures (in which you are likely to be much farther from your subject) or for wide-angle shots (in which you are likely to be much closer). You'll also be able to choose whether your flash fires automatically as required, flashes always (useful in some situations), or is always off. With one of my digital cameras, these flash settings apply only when the flash has been popped up from the camera body; you must remember to flip up the flash when it's needed.

It's also useful to be able to use an external flash unit not built into your camera, particularly when you want to use multiple flash for sophisticated lighting, as with portraits. Some digital cameras have a special connector for an auxiliary flash. Keep in mind that those cameras may require that you use only a particular brand of flash, too. (If you don't, the electronic triggering mechanisms may not match and you can "fry" your camera's flash circuitry!)

Viewfinders

Viewfinders have come a long way in the last 20 or 30 years in terms of the amount of information they provide the photographer. Figure 2.22 shows the display found in a traditional film camera's viewfinder when I started as a photographer, compared to the view today through a typical digital camera's viewfinder.

Figure 2.22. In ancient times, shutter speed, f-stop, and an exposure indicator were the only data displayed in the viewfinder (top). Digital cameras provide a lot more information! (bottom)

Today, virtually all digital cameras have both an optical viewfinder or electronic viewfinder, which both can be used to quickly frame an image, as well as an LCD display screen on the back of the camera for more precise composition and picture review.

The only things you need to check when selecting a camera is to see how visible your camera's LCD display is in bright daylight, whether it is large enough to view easily (most digital cameras use a standardized 1.8 inch LCD component), and the amount of power it consumes. The LCDs on some cameras consume so much power that, if left on all the time, you may find yourself with dead batteries after only a dozen or so shots. (Organic Light Emitting Diode (OLED) displays may help provide lower-power displays in the future.) Active-matrix displays are among the brightest and most power efficient. Some cameras let you turn on the LCD display only when it is required to compose a picture. One camera I use has a sensor that turns the electronic viewfinder display on only when your eye is pressed against the viewing window. It can also be set to automatically switch between the LCD and electronic viewfinder.

Most of the time, you'll be using your digital camera's optical or electronic viewfinders. The location can be important. A window-type viewfinder (non-electronic, non-SLR) provides a slightly different view from what the lens sees, which means part of the image you see may be clipped off when you're taking a closeup. Placing the viewfinder as near as possible to the taking lens reduces the tendency to chop off the tops or sides of heads or other subject matter. Many optical viewfinders have compensation (called parallax compensation) that clearly shows the limits of your image. Remember, you can also use the LCD display when framing is important. We'll look at these factors more in later chapters.

Of course, if you have a high-end single lens reflex (SLR) digital camera, you will view your subject through the same lens used by the sensor, giving you a much more accurate preview.

If you wear glasses, you'll want to make sure your optical viewfinder has built-in diopter correction (like that found in binoculars) that you can use to adjust the view for nearsightedness and farsightedness. With such an adjustment, you may not need your glasses at all to see the viewfinder image clearly. If you must wear your glasses while you shoot, make sure you can see the entire field of view. Sometimes a ridge or bezel around the viewfinder may prevent someone wearing glasses from seeing the entire subject area.

Other Features

Once you've chosen your "must have" features for your digital camera, you can also work on those bonus features that are nice to have, but not essential. Here's a list of some of the most common bonus features.

• Voice recording. Some digital cameras let you add a voice message to annotate your images with a few seconds of sound. Vacation snapshooters will find this capability valuable for keeping track of what photo was taken in what city (or foreign country). Photo hobbyists can record shooting conditions and other information about how the picture was taken (thankfully, digital cameras can record data like shutter speed and aperture used right in the digital file). Photojournalists can keep track of the people in the photo ("left to right are. . ."). This is a handy feature.
• Video recording. Most non-SLR digital cameras let you record short video clips at low resolution, usually at least 30 to 120 seconds worth of motion at 640 x 480 pixel resolution (or more). Some can record continuously until your memory card fills up. This capability will never replace a camcorder, but short movies can be interesting. If you want clips to put on a website, these digicam videos may be exactly what you need.
• Video output. Many digital cameras have video outputs so you can view your pictures on a TV screen without transferring them to a computer first. This is great for previews, and can turn your camera into a portable slide projector! If you're shooting tabletop setups, model train layouts, portraits, or other pictures with a relatively fixed camera position, using a TV as a monitor can be a great way to fine-tune your compositions, or let your portrait subjects see how they look before you snap the shutter. Video output is also handy for reviewing your vacation photos in your hotel room.
• Power options. The available power options a camera offers can be important. Some models use only proprietary battery packs, which can cost $40 or more, and may not be easy to replace in a hurry if your battery goes bad unexpectedly. Other models accept standard AA-sized batteries, so you can use cheap alkaline cells, which you can pick up anywhere in a pinch. Alkalines won't last very long in a power-hungry digital camera with flash, LCD display, and perhaps a mini hard disk all vying for juice, but they'll work in an emergency. The ideal situation is to have a digital camera with power-saving features (most can be set to power down after a minute or two and some switch on the electronic viewfinder only when your eye is placed up to the eyepiece), and powerful nickel metal hydride or lithium-ion batteries. Opt for a compact fast charger that can revitalize your cells in 15 minutes to an hour or less, as shown in Figure 2.23, and be sure to purchase an extra set (or two) of batteries. Digital cameras also can use an AC adapter, which is often an optional accessory, and not very practical, anyway, unless you're shooting near an outlet.

Figure 2.23. A compact, ultra-portable fast charger for your nickel-metal hydride batteries is a must-have accessory

Bonus features like these are seldom factors in choosing a camera, but all other things being equal, they are gravy on the cake (to mix a metaphor).

You should, however, consider ease of use to be a feature. Some digital cameras have logical layouts, a minimum of buttons and modes, and are very easy to learn. Place a premium on being able to access the most commonly used features without wading through a series of menus. The most frequently accessed features vary from person to person: You may use manual focus or exposure compensation frequently. Someone else may live or die by their ability to adjust shutter speed on a whim.

For that reason, I recommend that you try out any digital camera you are considering buying before you purchase it. You may have bought your DVD drive over the web, but a device like a digital camera, with so many controls and features, is not something to buy through mail order, unless you've had a chance to borrow the same or similar camera from a friend or colleague. Give it a real testdrive, using the typical features that you will need. No matter how ideal the specifications may be, until a camera has passed your own ease-of-use test, don't consider purchasing it.