December 30, 2006
32-bit/HDR improvements in Photoshop CS3
Photoshop CS2 introduced the application’s first support for 32-bit high dynamic range (HDR) imaging. The support was pretty limited, consisting of the Merge to HDR command (for combining bracketed shots into a single image) and some basic imaging functions (cropping, cloning, conversing from 32 to 8 or 16 bits per channel). Even so, about a year ago examples started popping up of HDR experiments (not solely connected to Photoshop, of course, but helped along by CS2). In the time since then more good resources on the subject have emerged.
The Photoshop CS3 beta includes some improvements in the HDR realm. Some more functions (e.g. Levels) are enabled for 32-bit images, and the Merge to HDR command, although superficially similar to the one in CS2, contains a variety of improvements. It benefits from the new image alignment code; preserves a more complete set of source data; and uses improved algorithms for merging the data.
Trevor Morris has kindly supplied an HDR photo created with the CS3 beta, as well as the source frames. He says, "I could never get it to work in CS2, but it worked flawlessly in CS3, and I was quite pleased with the results." He writes,
This photo was shot inside the Christ Church Cathedral, located in Fredericton, New Brunswick, Canada.
For this particular shot, I used a tripod and remote to capture 12 exposures, from 1/125s to 20s, with a Nikon D70 @ f/16, ISO 200, FL 18mm. I combined the exposures using Merge to HDR, increased the local contrast, and gave the image a slight saturation boost.
Give it a whirl with your bracketed shots, and please let us know whether it works well for you.