D-SLRs: Entry-Level, Midrange, Pro
What’s the difference?
Digital SLRs are the most versatile cameras, and for many photographers, the best choices. There are three basic categories of D-SLRs: entry-level, midrange and pro. These aren't exclusive categories—there are working pros who use midrange models, advanced amateurs who use models from all three categories and even well-heeled novices who buy top pro models (which, in program mode, are as easy to use as any entry-level model, albeit somewhat bulkier). But most models fall into one of the three categories.
Before exploring the categories, let's look at what the digital SLRs have in common and how they differ from compact digital cameras.
The defining feature of an SLR is its through-the-lens reflex viewfinder. When you look through the finder, you're seeing the image produced by the lens (reflected and "bent" by the mirror and prism, but the actual image nonetheless). SLR finders make it easy to check focus and composition, even at very close focusing distances. Optical finders in compact cameras don't "see" exactly what the image sensor sees, making for framing problems at close shooting distances.
Some compact cameras provide electronic viewfinders that do show the image through the lens, but the image isn't as good as with an SLR, especially with moving subjects. Of course, nearly all compact digital cameras have live-view LCD monitors that show the image through-the-lens live. This is handy but has two disadvantages: The LCD image is hard to see in bright light, and holding the camera away from you using the LCD to compose a scene is conducive to blurred images because of camera shake. The live-view LCD monitor is making its way into D-SLRs, with the pioneering Olympus EVOLT E-330 now joined by half a dozen current models offering live view in one form or another; but it's hard to beat an SLR finder for general shooting.
All D-SLRs accept a wide range of interchangeable lenses, while compact cameras have built-in lenses. Some compacts have a single-focal-length lens, most have a moderate-range zoom, and a few have wide-range zooms. But in any case, the inability to change the lens that's built into the camera limits your shooting options. (There are telephoto and wide-angle adapters available for many compact digital cameras, but the focal-length range still doesn't match that of a D-SLR's lens lineup.) Of course, you have to buy (and carry) each D-SLR lens separately, which isn't a good thing for many users.