High Dynamic Range Photography - A Look Behind The Scenes

High dynamic range photography, once a little-known photographic technique, has become one of the latest trends in digital imaging. HDR photography allows the photographer to combine multiple images with different exposures in order to yield a broader range of contrast and, as such, is especially useful in situations with both highlights and shadows. Digital camera technology has made the technique more accessible as well as more versatile, since image processing is merely a matter of manipulating bits; despite the advantages of digital imaging, there are still limitations and characteristics behind HDR techniques, details that can be both interesting to know and useful in defining and refining your personal technique.

One of these issues is dynamic range; while many, maybe even most, photographers realize that there’s a lot more dynamic range out there than their cameras are capable of seeing, not all of them know just how much or realize its effects on factors other than their camera. Obviously, the human eye is capable of detecting a remarkable degree of variation in luminance (well in excess of 20 f-stops, in comparison to 10-12 on a "contrasty" day, but how do your other devices stack up?

In the case of your digital camera, it depends - because of how CCD and CMOS devices detect light, the size of the sensor’s photodetectors and how they process their resultant electrons effect their sensitivity to dynamic range. Larger sensors increase the detectable range before “blow-out” occurs through a higher saturation threshold, while the detection strategy that charge-coupled device-based sensors utilize gives them something of an edge over complementary metal-oxide semiconductors in dynamic range. All things being equal, DSLRs have the advantage in dynamic range, due to their larger imaging sensors. Still, under the right circumstances, high dynamic range photography can even matters up - as long as conditions favor it, of course.