AFRIGRAPH 2004 Paper
SIGGRAPH 2004 Poster
We present a technique for capturing the extreme dynamic range of natural illumination environments that include the sun and sky, which has presented a challenge for traditional high dynamic range photography processes. We find that through careful selection of exposure times, aperture, and neutral density filters that this full range can be covered in seven exposures with a standard digital camera. We discuss the particular calibration issues such as lens vignetting, infrared sensitivity, and spectral transmission of neutral density filters which must be addressed. We present an adaptive exposure range adjustment technique for minimizing the number of exposures necessary. We demonstrate our results by showing time-lapse renderings of a complex scene illuminated by high-resolution, high dynamic range natural illumination environments.
For capturing the sky we used a Canon EOS-1ds with a Sigma 8mm lens. To control the camera, we used the Canon Digital Camera SDK. This C library provides the ability to set camera settings such as F-stop and exposure time, release the shutter remotely, and download images via firewire or USB.