Monday, January 29, 2007
D-SLRs Vs. Advanced Compacts
Both digital camera types offer real advantages—which one is right for you?
While speed isn't too critical when you're shooting still lifes on a tripod, a camera's responsiveness makes a big difference in capturing a fleeting moment. Whether shooting sports-action or catching your child's expression, a fast-acting camera will make the challenge easier.
D-SLRs are faster across the board than advanced compact cameras. They boast a swift shutter release and acquire focus more quickly than advanced compacts. D-SLRs also have a larger image buffer, letting you shoot more images in succession before the camera has to stop and write the data to your memory card. In short, D-SLRs' ability to fire now is a major reason that so many shooters put up with their greater bulk.
While shutter lag times for the current generation of advanced compacts are dramatically shorter than earlier models, these cameras aren't your best choice for shooting action sequences. Advanced compacts' slower shooting speed is offset by the fact that the cameras' light weight makes them likely to come along with you when your D-SLR would have been left home.
Although most D-SLRs' sensors are about one-third smaller than 35mm film, these "small-format" D-SLR image sensors dwarf the tiny sensors found in advanced digital compacts.
You might think that D-SLRs' comparatively larger sensors would give you more pixels, but you easily can find advanced compacts with as many or more megapixels on their sensors than their D-SLR brethren. The real difference between the two sensor types is that the bigger image sensors in D-SLRs allow more physical space for each pixel's actual photosite. Photosite size has a dramatic impact on ISO settings, noise and overall image quality.
ISO And Noise. A typical D-SLR offers ISOs in the range of 100 to 1600, with "boosts" up to 3200. At their lowest ISOs, properly exposed D-SLR images are silky smooth, with no noticeable noise. Even images shot at ISO 400 still will enlarge beautifully. Apart from the outstanding clarity of midtones and highlights, the D-SLR's lack of noise also allows you to pull out a greater measure of shadow detail without sacrificing image quality.
In contrast, most advanced compacts can manage ISOs from about 50 to 400. Advanced compacts' images tend to be more noisy than those from D-SLRs, with a texture reminiscent of 35mm film. At the cameras' lowest ISOs, correctly exposed images can turn out stunning results, but at ISO 400, noise will be very conspicuous.
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