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Tuesday, May 22, 2007

The Art Of The Up-Res

Getting beyond the limitations of your camera's native resolution is an art and a science

The Art Of The Up-ResDon't let anyone kid you; size really does matter—when it comes to digital capture, that is. But what you do to get that size is even more critical. Before we get to the process, let's cover some ground rules.

Proving the techniques outlined here needs to be done on your own files with your own output requirements. You need to test this stuff for yourself. It's rather difficult to convince someone that a 16–megapixel image interpolated from about 11x16 inches at 300 ppi (4992 x 3328 pixels) to 44x66 inches at 300 ppi (19,968 x 13,312 pixels) is going to “look good.” It will if done correctly, but you have to see it to believe it.

None of what I tell you can make up for poor photographic technique. If you want to interpolate your files way up in size, you'll soon learn the harsh fact that a poorly captured image won't get you there. Cheap lenses, camera shake, bad exposures leading to noisy images and poor camera composition, as well as radical cropping, won't lead you to nirvana. “CSI” is a nice TV show, but stuff that's soft, out of focus or noisy will remain that way, only bigger, when you up-res in real life. A tripod or fast shutter speeds and understanding proper digital exposure and cropping are critical. While post-processing can help, it can't eliminate technical defects.

You also should note that I'm not a particularly “independent authority.” I have relationships with a camera company, a printer company and several software companies—none of which has any impact on my opinions or personal experience one iota. But my personal workflow uses a subset of tools available in the marketplace. I don't pretend to be an expert at every possible method of doing what I do, only my own method.

Challenges Of The Medium

If you wish to maximize the resolution of your digital camera, I'm here to show you a way that works pretty darn well. I still have the problem of trying to show it in the venue of a magazine with a page size of only 8½x11 inches. As a result, I've had to devise some unusual methods of showing you the results. Many of the images here are screenshots shown at various zoom ratios in Photoshop CS2. Just showing you crops of the real images is limited in its ability to convey what you would see on screen. In fact, even looking at images on a computer display isn't useful versus actually seeing how an image will print; while we can soft-proof color using profiles, we can't accurately soft-proof what pixels will look like on paper.

There are two main stories here: how to take lower-resolution digital captures and interpolate them up as though they were from higher-resolution cameras—not too hard, really; and how to take a nice large digital capture and make it really, really big. That's a bit more difficult.

Figure 1









In the meticulous and highly exacting manner for which he's renowned, Jeff Schewe illustrated this article by taking a still-life image with two different cameras under identical studio conditions. ABOVE, LEFT: The RAW image from a 6-megapixel D-SLR opened in Adobe Camera Raw. ABOVE, RIGHT: The same setup photographed with a full-frame, 16-megapixel D-SLR. The focal lengths of the lenses were different to account for the different sensor sizes.

Moderate-Sized Capture To Large File

I photographed the same scene with two cameras. Figure 1a was photographed with a lower-end 6-megapixel D-SLR; Figure 1b shows the same scene shot with a 16-megapixel pro-level D-SLR. The 6-megapixel camera used an 18-55mm lens while the 16-megapixel camera had a high-end 24-70mm lens—both reasonable lenses for their respective cameras, but the 24-70mm is a much finer lens; it better be since it costs about 12 times more money!

The images were processed via Camera Raw 3.1 in Photoshop CS2 with minimal settings adjustments, no sharpening or luminance smoothing, and with a default color noise reduction of 25. The only preprocessing of the RAW files was conversion to the DNG RAW format.



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