We are fast approaching autumn, and with it many enjoyable walks in the woodlands with a camera at the ready. This past weekend we visited Pfeiffer Big Sur State Park on the central California coast. It provided a warm-up for autumn photography. One feature of forest scenes is the high range of light to dark tones. That prompted me to brush up on high dynamic range imagery (HDRI), a technique for combining multiple exposures into a single image.

Here is the nominal exposure for a forest scene. The highlight detail is lost and the shadows are too dark. The problem is generally worse for digital cameras, which have perhaps a half stop less dynamic range than film. The HDRI method is described in a tutorial on our main site.

It’s been a while since I’ve used Photomatix™, a standalone program for performing the trick of merge three exposures. I downloaded the latest version and applied it to a three-frame sequence of the forest scene shown above. Exposures were bracketed +/- 1.5 stops with my Nikon D80, handheld.

A characteristic problem with the HDRI technique is motion of the subject between frames. The software performs an alignment of the frames to compensate for camera movement, but the smallest of breezes will flutter the leaves and move small branches. Photomatix offers options to correct either subject motion or background motion. Even though leaves are moving in the background, they are still a candidate for “subject motion.”

Here is a close-up of the HDRI output without subject motion detection enabled:

And then with the motion detection selected on “high”:

Thanks to Photoshop™ sharpening and, more importantly, reducing the resolution to blog size, the final HDRI image looks fairly sharp:

HDRI is also useful for rendering intensely blue autumn skies.

A bit much, don’t you think?

My Photomatix skills need sharpening as well. The current version has quite a few options and adjustments I have yet to figure out. It’s one of those mighty powers that could be invaluable, if only it can be mastered.