Readers of some of our other camera reviews have sent email asking us to provide some technical photography definitions, and we're happy to oblige. The acronym SLR stands for Single Lens Reflex. TTL stands for Through The Lens. Dynamic Range is a term for the range of light and color (from darkest to brightest) that a digital camera sensor can capture in one photo while still retaining discernable detail in the brightest and darkest parts of the photo. The acronym ISO, in the photography world, stands for International Standardization Organization standard 5800:1987 (among others). Camera film is rated according to whether it's color or B&W, how sensitive it is to light, and which film development process is required. For digital camera purposes, the camera sensor designers have settled on an ISO calculation and engineering standard which quite accurately approximates film light sensitivity at all combinations of shutter speed, aperture and exposure compensation settings. The word Noise in digital camera terms is essentially the digital version of what camera film makers call Grain. While digital Noise appears as unwanted randomly arrayed specks of color, film Grain appears as a regular pattern of texture on prints and slides. Using a film camera with ISO200 color print film and a digital SLR set to ISO200, both cameras using the exact same lens, with all other things being equal (aperture, shutter speed, lighting conditions, subject matter, location, etc.), you'll get substantially identical exposures in test photos. While color tone, color saturation and contrast may vary between the two photos, the most important differences occur when you attempt to push film to higher ISOs or allow your digital SLR to automatically increase the ISO in order to properly expose shots. With film, Grain becomes more noticeable. With digital, Noise increases. The best digital SLR cameras now offer sensors which function essentially noise-free at absurdly high ISO settings (1600, 3200, and even 6400). Everyone concerned about noisy digital photos should realize too that, up to a point, a little noise that's faintly visible in a photo being viewed on a monitor often does not show up when you print.

P&S and prosumer cameras are designed with a lens that is integrated and permanently attached to the camera body. SLR cameras are designed as camera bodies only, but with a lens mount specifically engineered for a particular brand of lens and mount configuration (Nikon and Nikkor lenses are designed to work only with Nikon and Fuji SLR cameras, Canon lenses are designed to work only with Canon SLR cameras, and so on for each camera maker). P&S and prosumer cameras offer advantages which include lighter weight, smaller size, good to very good image quality, lots of features & functions for the more technically minded amateur and hobby shooters, and usually significantly lower cost compared to most SLRs. As long as inclement weather, rough conditions, fast movement and moderately diffcult lighting conditions aren't involved, it's possible, in the hands of a photographer attuned to the finer points of composition, subject matter and lighting, to produce near-pro quality photos with many P&S and prosumer cameras. Entry-level SLRs offer advantages which include very good to excellent image quality, significantly better dynamic range than any P&S or prosumer camera, fully automatic or fully manual operation and every increment in between, as well as a wide selection of very good to superb quality fixed focal length and zoom lenses. In the right creative hands, any entry-level SLR from Nikon, Canon, Pentax, Olympus and Sony can be used in an enormous range of lighting and weather in an almost limitless range of situations to produce professional quality photographs

So what do semi-pro and professional digital SLRs have that entry-level SLRs don't? Enhanced weather proofing, tougher bodies meant to take much rougher treatment, fine-tuned picture controls for the most technically appropriate camera settings that can be tweaked location by location, subject by subject for the most accurate color control (among other things), more advanced image file management, more accurate automatic white balance, brighter and large viewfinder, brighter and more accurate LCD screen, more versatile external controls, more versatile focus control and better high ISO/low noise image production. None of the high-end features found in more expensive cameras mean anything if the photographer doesn't understand composition, lighting, white balance and exposure compensation.