What’s this? Unavoidable digital artifacts? Using an analog-designed lens on a CMOS sensor? Pixel bleeding (I thought CMOS was immune to that)? Correctable chromatic abberation? Anyone got a clue? FYI, I’m shooting primarily with a 28mm-135mm IS, or a 17mm-35mm.
I’m accustomed to the distortions inherent in using film. I like most of them, generally. I like the texture of grain, and the way highlights can diffuse. I use multiple techniques to degrade image quality all time—filters, breathing on the front of the lens—but I’d prefer to be in control of it. Here is a whole new order of distortion that is, well, ugly. In shots where I have a light source in the image, I often see red and blue fringing around the edge. It may be that now I have to invest in lenses designed for digital too.
As I understand it, this is a result of the difference between how a sensor and how film responds to light. Film can detect light striking it from any angle. In a wide angle lens, the angle can be quite oblique on the edges. Digital is sensitive to light only when it strikes perpendicular to the plane of the sensor. Which requires a different optical design. I had hoped that the smaller sensor, seeing only the center section of the lens coverage, would save me from this problem, but I suspect this is not the case. And that I’m about to overhaul my entire lens collection too.
CA or chromatic aberrations have been an on going problem with all digital sensors. I have found that the 1ds and higher resolution digital sensors have less of this problem but regardless of what lens you use on your camera if you try to shoot high contrast dark foreground bright white backlight your going to see some CA. I have a few tricks for getting rid of it in Photoshop if you’re interested, although I'm sure you've already dreamed up a few ways yourself.
Posted by: stephan | December 30, 2004 at 11:17 AM