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How-To

Optics In A Digital World

Lenses are limited by the laws of physics, but software can help remove some of those limitations

While the prices of digital cameras continue to drop, lens costs aren’t keeping pace. The reasons for this are pretty simple. Lenses don’t follow the computer-based Moore’s law that states changes will occur exponentially. They must follow the laws of physics.

And yet, there are things happening with lenses today that offer us new possibilities with how optics affect our images. These are, to me, quite interesting as they offer both quality and creative enhancements to our gear, increasing the possibilities of our equipment.

One thing that higher-megapixel cameras have done is stressed the capabilities of lenses originally designed for 35mm. Many photographers are discovering quality limitations with lenses that worked great with film but exhibit their defects with sensors of 10 megapixels or higher. Manufacturers then have to come out with redesigned lenses that better meet the requirements of digital. This is a clear indication that many digital cameras have passed the capabilities of 35mm film.

Software does come to the rescue. In fact, DxO Optics software can increase the image quality of a photo taken with certain lenses and sensors. DxO is quite a remarkable program. The engineers at DxO actually measure the performance of lenses with specific sensors, then create corrections based on that unique combination to give you a file with the highest-quality image.

Image sharpness, brilliance, aberration correction, vignetting and more are analyzed and adjusted automatically by the program. The technology behind this is pretty heady—I only understand some of it. But I certainly understand the excellent results. This can mean you get more from an older lens or that you improve results from a less expensive lens.

Adobe has also put some basic lens-correction capabilities into its software. Photoshop CS3 (and CS2), Camera Raw and Lightroom all allow you to correct some color aberrations as well as vignetting caused by the lens. This isn’t as refined or sophisticated as DxO Optics, but it does work. In Photoshop, these are under Filter > Distort > Lens Correction. In Camera Raw, look for them in the Detail tab. And in Photoshop Lightroom, you’ll find them in the Develop Module in Lens Corrections.

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