Most digital camera test reports on the Internet devote several pages to image quality at ISO 1600 and above. Now that I’m ready to trade up from a digicam to a DSLR, should I be really concerned about high ISO performance? When I was shooting with a Nikon F-601, I usually used ISO 100 to 400 film, and on a few occasions, Fujicolor 800, so why is ISO 3200 so important now? S.W.
Your question makes a valid point, S.W. In conventional photography, few photo enthusiasts ever used the very “fast” films. In fact, most retailers did not even stock print film faster than ISO 800 or slide film faster than ISO 400. But since digital cameras include built-in high sensitivity options — up to 6400 or even to 25,600 in some cases — this aspect receives a great deal of attention. And that’s not surprising, since high ISO quality is one obvious method for comparing various cameras.
Hence, consumers expect any detailed review to at least mention this aspect, even if it’s not one of the primary criteria for deciding which model is “best”. Especially today — when an increasing number of cameras and lenses are equipped with an image stabilizer — we rarely need to use an ISO above 1600. That level provides an adequately fast shutter speed to prevent blurring from camera shake in most low-light situations. In my own photography, I switch to ISO 3200+ only when shooting indoor sports; then that option is essential for a fast shutter speed to freeze the competitors’ motion.
Unless you intend to frequently photograph moving subjects in low light — or to shoot in unusually dark locations without flash or a tripod — you should be more concerned about other issues. That should include image quality at your most frequently used ISO levels, continuous autofocus performance and burst speed if you often shoot sports, convenience of operation, versatility, and the accuracy of exposure, white balance and autofocus. Since camera reviews also cover those aspects, simply concentrate on the most relevant sections of any test report instead of getting bogged down in high ISO photo comparisons.