Tuesday, November 24, 2009
Will The Megapixel Wars End?
As resolution climbs into the stratosphere, pixel counts aren’t necessarily the most important specification in a D-SLR
To handle the 21.1-megapixel, full-frame images turned out by the EOS-1DS Mark III, Canon gave the camera not one but two DIGIC III image processors. Top processing assures top image quality and allows shooting the big files at 5 fps.
Resolution has climbed steadily in that time frame, as well. Two mega-pixels has blossomed to more than 20 megapixels on some models. While some people continue to make comparisons to film, that discussion has died out almost completely. Today, if you want to shoot film because you like it or you think you get better results, so be it. You like the look and the workflow, and it’s working for your photography, so more power to you. But film versus digital really isn’t much of a battle to see which technology will win out anymore. That war is over. Manufacturers like Kodak and Fujifilm make some fantastic emulsions, and we hope they’ll continue to do so for many years because there continue to be photographers who want to shoot film. But digital sensors are so good now that the meaningful debate about which yields supe-rior images is done.
Just about any professional cringes at the thought of interpolating an image to a higher resolution than the native dimensions. The very word “interpolation” is imbued with a derogatory connotation, but let’s discuss why that’s so. Interpolation’s bad reputation stems from the period when sensors had a fraction of their current resolution. A 3-megapixel sensor might yield a 10-megabyte image file. If you tried to boost the resolution with software, you could get a much larger file, but at some point, the interpolation software just didn’t have enough data to work with, and so the resulting image began to break apart, and you ended up with an unsatisfactory image. Pros who have grown up, profession-ally speaking, with digital technology recall only too well how clients and stock agencies refused to accept interpolated images because of the risk of poor image quality from the interpolation process.
If we look at interpolation in terms of a modern high-resolution D-SLR, it’s a different story. At 12+ megapixels, digital image files that come off the camera open to about 40+ megabytes. That’s a lot of data. Assuming you’re shooting RAW, the image files should be almost completely free of artifacts (even RAW images go through compression and processing, which can lead to some, albeit minimal, artifacting). With that much distinct image data to work with, interpolation software can do a much better job. Essentially, interpolation software likes to work on data. The more data it has, the better the results. Furthermore, the scale isn’t linear. Having four times as much raw image data will yield much more than four times as large a final file if pushed.
So we can see that, by all accounts, it’s difficult to characterize today’s megapixel counts as lacking. Still, many manufacturers have been loath to slow the progression. On the marketing side, megapixels still give the camera a focal point and a well-established specification that most buyers understand. Especially in trying economic times, it’s not easy to make the argument that the megapixel race should be reconsidered, but there are some good reasons to do just that.
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