Just When You Thought You Knew...
Chapter XXXVIII: In-Camera Sharpening
By Don Sutherland
It's always useful to discuss This Week's Trends showing up in the latest digicams. This week's? It sure seems that way. Remember when all there was to discuss about digicams was "resolution?" How many pixels they had? The business has come a long ways since those ancient days of 1996, and digital cameras now have a variety of features that never existed before — in any kind of camera. I've been publishing the updates since time immemorial, originally under the title, "Just when you thought you knew how to sell cameras."
And yes, in our delirious digital domain, we find little in common between the solid-state picture-taking devices of today, and the fare crossing the counter when shutter speeds were controlled by springs. In those days, a camera demonstration might have emphasized how securely the camera back locked after inserting the film, or how conveniently located the knob or lever might be to wind-up the film. It's all moot today, as digicams have neither reason to open or close, nor do they have much to wind up.
The bragging points in cameras today turn their backs upon traditions in design going back to the 19th century. In their place, we brag about a new range of stuff, such as how much control the camera allows the user to exercise in sharpening each picture taken.
Now, how sharp or unsharp a photo would be was always a user-controllable feature, to the extent that aperture setting, focal-length, and depth-of-field have always affected sharpness, and have always been more-or-less user-controllable. Ditto the quality of the lens. These factors are just as strong an influence on digicams today. But along with all that, digital cameras this week are offering a form of sharpness control that film cameras never did, and that digicams didn't either, until a few moments ago.
Whaddaya mean, "sharp?"
When consumer-market digicams commenced their eruption in 1996, one of the most heartfelt observations about them was that their quality was lousy. Return rates as high as 50% were reported in this very column, and that was no way for digital photography to get ahead.
Veterans of our five-year-old industry, those whose company histories include a lot of high marks for optics, attribute the early discontent to Coke-bottle lenses. Some of the first digicams came out of the gates of makers who hadn't really made cameras before. They'd made plenty of electronic devices, and might rightly be proud of their achievements with CCDs. But CCDs alone do not pictures make.
In time, the importance of optical quality was accepted more broadly, and now most of the majors have stories to tell about lenses. In fact, this was one of last year's major trends. Olympus was among the first and most vocal to describe the importance of lenses purpose-built for digital imaging (as opposed to lenses optimized for film). Since that time, Schneider, Zeiss, and even Leitz lenses have been featured attractions of various digicams and digital camcorders. Fujifilm has its own boasts, Fujinon lenses having long been standards in broadcast TV.
The digicam industry has refuted the bad reputation it sustained in the early days for optical sharpness, but there's a residual defensiveness going around. Digital cameras are better — much better — than they were before, but except for certain studio models, they still don't match the sharpness of film. There's a good chance they never will. So manufacturers continue to keep the issue of sharpness in mind.
Edge-sharpening can be accomplished in software too, including software in digicams. But till recently, the degree of sharpening has roamed all over the lot from maker to maker and model to model, with mixed results. And till recently, the degree of sharpening was permanently set for each.
Obscurity with a hard edge.
How do you "sharpen" a digital image, anyway? Tracing a hard edge around a subject in parts of a scene is one way of making the picture look snappier. It was used in movie camcorders before the succession of still-picture digicams began. It goes back to old graphic traditions where, for example, a retoucher working at a newspaper might take a pencil and draw a line around a subject, if the contrast between it and the background was insufficient for good reproduction on newsprint.
Depending upon other factors of color and contrast, a given subject in a digicam today might be endowed by software with an outline of, say, black or white. In a full-motion video, this outline tends make the edge more discernable without really being discernable itself. With things clipping along at 30 frames per second, you don't see the outline so much as you see what seems like a better-defined, sharper subject.
But in a still-image frame, the outline doesn't whisk around the screen like a nearly invisible presence. It hangs there in plain view, like the halo around any church-window saint. Years ago, I photographed a woman in a robe as she strolled along the beach. In the picture, her robe was surrounded almost entirely by a border of white. Was this the result of edge-sharpening, or did her robe have a fringe of piping around it in real life? I couldn't remember, so I had to phone her and ask.
On the day of my goddaughter's christening, I photographed her and her parents backlit against a window. The lighting provoked a software response, which was a black line along her father's shoulder. It was much less ambiguous than the fringe around the robe, but no less intrusive. It looked just like the heavy-handed work of a retoucher's pencil.
As such blatant evidence of retouching, does the black edge make the picture unsatisfactory? So unsatisfactory as to warrant returning the camera, for the same reasons that Coke-bottle lenses once did?