Armação Nova just before sunset.Very easy to find interesting compositions, the first image on the right is my favourite from this session.
Camera Contax AX, Lenses Zeiss Distagon 21mm + Zeiss Distagon 15mm, Film Fuji Velvia RVP, self-developed.
Cameras Film: Sinar F2 4×5, Horseman LS 4×5, Zeiss Ikon RF, Zeiss Contax III (1938), Contax AX. Film: Ektachrome E100G, Velvia 50, Provia 100F, Fuji Acros 100. Cameras Digital: Canon EOS 5D (modified), Epson R-D1. Lenses in use:
Today we present our technique for capturing the complete dynamic range of a natural illuminated enviroment, sun and sky included. This has nothing to do with the tonmapping of HDR images. It’s a technique to use the captured light from photographs to illuminate 3D scenes in CG applications.
Developed by Paul Debevec, the father of image based lighting and his team, the capturing of the full dynamic range of the sky and the sun is still a challenge.
Our goal is to capture sun and sky, to use it for illumination for static and animated 3D scenes, under physical corrrect parameters, rendered with Global Illumination, using unbiased Brute Force algorithms in our 3D application.
We found out that we can cover the full range in ten different exposures, using varied and optimized shutter speeds. Working with special filters such as neutral density filters, to reduce the amount of light and IR-cutoff-Filters, to reduce the camera sensors IR response. We have developed a special software, which allows us to control the best exposure time and downloading the images directly to our server, for further development.
Working with ten exposures for each one-second lightprobe, you can imagine the large data created, by capturing a complete hour of daylight. Each hour needs more than 600 images, resulting 14400 images per day. Which is not only a storage problem, because modern highend DSLRs are designed to guarantee ~ 150000 – 500000 shutter actuations. You can imagine the short lifespan of a modern DSLR after capturing a day of sun and sky.
Exposure Example: 1/8000 f16, 1/160 f16, 1/30 f16, 1/15 f16, 1/30 f4, 1/10 f4, 1/4 f4, 1/2 f4, 1” f4
(theres nothing wrong with the black images, you can see the sun at the lower end)
Some different renderings on our very simple 3D test scene:
1 3D wireframe of the model
2 3D plain rendering, using no lightsource in the scene
3 3D, using a skylight without global illumination/radiosity
4 3D, skylight with GI/radiosity
5 3D, the Skycapture result, using the 10 exposure HDR-file, with GI, accurate shadows from the physical sun and the sky and reflections from the HDR
Finally three samples, rendered with our 3D model of the Berlin Palace, using three different light situations, 10 stop HDRs:
By writing this, we are working on a unique HDR collection, with single and timelapse skies, for many different renderer and 3D applications.