Digital Photography For Dummies. Julie Adair KingЧитать онлайн книгу.
been around for a long time. SLR stands for single-lens reflex and refers to the viewfinder technology used in this type of camera. The name stems from the fact that the SLR viewfinder involves a series of mirrors that reflect (reflex) the light coming through the lens to the viewfinder display.Although dSLRs were once large, heavy, and complicated, manufacturers now also offer models geared to novice photographers as well as advanced shooters. High-end dSLRs still remain fairly large, but entry-level and intermediate models are available in significantly reduced sizes. The smaller of the two dSLRs in Figure 1-1 isn't much wider than the compact, fixed-lens model or, for that matter, the smartphone.
Mirrorless cameras: With this type of camera, the mirror-based viewfinder system is gone — thus, it's mirrorless. Taking out that mirror assembly enables mirrorless camera bodies to be smaller and lighter than dSLRs. Figure 1-7 shows a top view of a mirrorless model next to a small dSLR for comparison. I show both models without a lens attached so that you can get a better idea of how the mirrorless design affects the size of the camera body. However, not all mirrorless camera bodies are as small as the one in the figure. In fact, some pro mirrorless bodies are a bit larger and heavier than the smallest dSLRs. Of course, the size of the lens you put on the body determines the overall bulk and weight of both types of cameras.FIGURE 1-7: Although it’s not always the case, a mirrorless camera body (left) is usually less bulky than even a small dSLR (right). Some mirrorless models do away with the viewfinder entirely; you compose the image using the monitor on the camera back. Others, such as the one featured in Figure 1-7, incorporate or enable you to attach an electronic viewfinder (EVF), which provides the convenience of a viewfinder without taking up as much space as an optical viewfinder, which is the type used in a dSLR viewfinder. The section “Viewfinder: Optical or electronic,” later in this chapter, has more details. Today, the hot commodity in the pro photography arena is a full-frame mirrorless camera. You get the image-quality and lens coverage benefits of a full-frame sensor in the smaller body afforded by the mirrorless design, all of which sounds good. However, these models are expensive; expect to spend $1,000 or more just for the body. And you can’t use your existing dSLR lenses without an adapter, which negates some of the size and weight benefits of a mirrorless system. If you want to ditch the adapter, you’ll have to buy new lenses specially designed for the mirrorless body you pick. Personally, I don’t have that kind of cash on hand, but as with all technology, prices tend to drop as time goes by, so … a girl can dream, can’t she?
Rangefinders: A less-common variety of interchangeable-lens camera, rangefinders look a lot like mirrorless models, but work quite differently. Traditional rangefinders use a different focusing system than other cameras. The viewfinder displays two views of your subject, and you determine the focusing distance, or range, by turning a ring on the lens until the two images align. Most rangefinders offer only manual focusing, although a few do also provide some autofocusing options. Leica is the best-known manufacturer of rangefinder digital cameras.
Fixed-lens cameras
Again, by fixed lens, I mean a lens that's permanently paired with the camera body. Cameras in this category fall into two camps:
“Real” cameras: That is, a camera whose sole purpose is photography, as opposed to a computer device or phone that sports a camera. Most people refer to these cameras as point-and-shoot models because they offer automatic settings that enable the novice photographer to, well, point and shoot. Yet I hesitate to use the term, because higher-end fixed-lens models do let you control exposure, focus, and other picture settings. And although you can't swap out lenses on these cameras, many models have zoom lenses that reach from wide-angle to telephoto views, so you still enjoy lots of picture-taking flexibility.Whatever you want to call them, these cameras come in a variety of sizes, shapes, and colors, ranging from models that look like a small dSLR or mirrorless camera to pocket-size wonders that make the latest smartphones look huge. You also can find models specifically designed for rugged use, offering features such as shockproof and water-resistant cases. These models are great not only for outdoor adventurers, but also for young photographers who may not always be as careful with their devices as the adults in their life would like them to be. Heck, I certainly don't qualify as a young photographer (although 60 is the new 59), and I can't be counted on to always retain a firm grip on my equipment, either.
Smartphone and tablet cameras: Of course, no book on digital photography today would be complete without mentioning the cameras built into these multipurpose devices. Providing specifics, though, is difficult because the capabilities of smartphone and tablet cameras vary so widely. On some devices, you can do things such as tap the screen to indicate the focus point or adjust exposure slightly, but other devices give you no control at all. Some devices offer multiple built-in lenses, each with a different focal lengths, while others limit you to a single lens and focal length. Suffice it to say that if you're going to use a mobile device as your main camera, do your research.
Also note that even though you can't swap out lenses on these types of cameras, you can often attach lens modifiers that provide a different angle of view than the built-in lens. Companies such as Moment (www.shopmoment.com) sell telephoto and macro (close-up) add-on lenses for smartphones, for example.
Looking at Lenses
As your camera's eye, the lens plays a huge part in what types of photos you can capture. It determines not only how much of a scene you can record in one shot, but also the quality of the image and certain other characteristics of a photograph.
When considering lenses, pay attention to the specifications outlined in the next sections.
Camera compatibility
Interchangeable-lens cameras require specific lens types. If you have a Nikon camera body, for example, the lens must have a Nikon mount. That doesn't mean that you have to stick with the manufacturer's lenses; you can get great lenses from third-party makers such as Tamron and Sigma. Again, just make sure that the lens offers the correct mount for your camera (or that you can make it work with an adapter).
Lens focal length
Now that I’ve done my due diligence in the technical explanation department, allow me to explain focal length in practical terms:
Focal length determines the lens’s angle of view. The shorter the focal length, the more subject area fits in the frame. Increasing focal length narrows the angle of view and makes your subject appear closer and larger. Figure 1-8 illustrates this fact, showing the same scene captured at four focal lengths. (A lower number indicates a shorter focal length.)Some focal length recommendations:Landscape photography: Look for a wide-angle lens, characterized by a focal length of 35mm or shorter.Nature and sports photography: Assuming you'll be shooting at a fair distance from your subject, you need a telephoto lens, which has a focal length of 70mm or longer.Portrait photography: Aim for a focal length in the range of 70–135mm. At other focal lengths, facial features can be distorted. A wide-angle lens, for example, can make your subjects appear sort of like how they look when you view them through a security peephole