Magazine Article


Digital Deal
Lenses, for a Change


The "35mm equivalent" was created. A 16mm lens might be the "35mm equivalent" of a 24mm lens on one digicam, a 28mm lens on another. It depends on the size of their chips. Either way, we get a workable sense of what the lens will do for the picture. At least we will from the angle-of-view standpoint. But other characteristics of a picture made by a 16mm lens wouldn't match those of a 28mm. The perspective and depth-of-field, for example, remain that of a 16mm lens.

The term "magnification factor" seemed like proper terminology to use with "35mm equivalents," but it wasn't completely accurate. Since only the angle-of-view matches the specified "35mm equivalent," the term "cropping factor" is better, because the frame is actually cropped on a physically smaller surface. This newer terminology seems to be catching on.

The Full-Frame Format

Just as the applecart was settling down, Nikon rattled it anew by announcing the D3, their first full-frame camera-full-frame in the sense that the imager matches the size of the 35mm negative, about 36x24mm. This eliminates the need for a "35mm equivalent" specification-a 16mm lens acts like a 16mm lens in every way.

Since Nikon had preached the superiority of their digital lenses on their digital cameras, the move was a surprise and, to some, a contradiction of their policies. First they tell us to use digital lenses, then they bring out a camera that can't use digital lenses because there are no digital lenses for the full-frame format (or, at any rate, digital lenses can't be used at full resolution; the 12MP camera drops to 5MP when digital lenses are mounted).

If it seemed like a marketing blunder at first, maybe Nikon's many enemies were fanning the heat; nothing is stopping anyone from producing full-frame lenses in the future, with the optical characteristics of digital lenses.

Nikon's decision was based upon the ongoing trend toward mega-megapixel cameras. The 10MP imager has already become entry level-you can buy a 10MP P&S with 3x zoom for under $200-and there are a half-dozen cameras at 14MP and higher. When you start reaching (and exceeding) those pixel counts, you have a choice to make.

Fitting 14 million diodes in the same space you previously fit 7 million requires reducing the size of the diodes by approximately half. And when the diodes get smaller, the pictures they produce tend to get noisier. So as the picture becomes "better" thanks to higher resolution, it becomes "worse" thanks to increased noise.

The improvements probably outweigh the detractions, with advances in noise-reduction software, but we start seeing compromises there, too. Noise-reduction routines also tend to soften the image. The more perfect solution: avoid the noise in the first place. And if you're going to ever-higher pixel counts, the best way to keep noise down is to use a larger chip, with larger pixels.

While Nikon received the occasional suspicious glance, Canon must have sat back and smiled. They've had full-frame cameras on the market since 2002 and presently offer two models (the 1Ds Mark III and the 5D). They've always said there's a time and place for large and small imagers, and they've produced lenses in both formats for years.

Rumblings of a full-frame Sony DSLR have been circulating. As pixel counts rise to 14 million and beyond-an ongoing evolution which we encourage-it should be no surprise if other full-frame DSLRs emerge.

Once we have a third full-frame camera manufacturer, we'll have an official and bona-fide "product category." With Olympus as the principal force behind the FourThirds standard, which gives a specific size for the imager, it's not clear how they would address a trend toward bigger chips. But nothing would have to stop Pentax, which, like Canon and Nikon, has APS and full-frame lenses in its lines already. Sigma makes lenses for both sizes, and the imager of their existing camera, the SD14, is already bigger than most APS chips. Who knows what would happen if Foveon went full-frame?

If full-frame cameras do become a category, there will be that much more for customers to consider and for the industry to explain. Which lenses you can use-and what cameras you should buy to be able to use them-will be a richer subject than before. We'll take a closer look at specific lens lines next issue.

Don Sutherland has sold cameras across the counter, shot with them as a pro, and written about them for more than 30 years. Don is a photo historian as well as a futurist, and is the author of the immortal slogan, "If you have one foot in the future and one in the past, you understand the present perfectly." Email Don at Go to for a ton of digital photos.