Zeno Pelgrims’ POTA Camera Shader Offers a Better and Faster Wide Lens Aberrations in Arnold.
Lens effects are expensive to render directly “in-camera,” even with some of the faster GPU driven renderers. Still, there is something warming and almost magical about rendering lens effects from a 3D scene. With many render engines you can apply lens or camera shaders to get the look of lenses baked in. With Arnold, if you are looking for something that has better (and more) aberrations like a wider angle lens, then you should take a look at Zeno Pelgrims‘ POTA Camera Shader.
P.O.T.A. (Polynomial Optics to Arnold) is a direct implementation of a 2016 white paper accredited to Emanuel Schrade, Johannes Hanika, and Carsten Dachsbacher Karlsruhe Institute of Technology, Germany, called Sparse high-degree polynomials for wide-angle lenses. POTA can render images that have higher-order aberrations at a fraction of the cost compared to tracing rays through physically plausible lens elements. The Camera Shader works by pre-calculating fitted polynomials which then applies a transformation to the rays. “The visual quality is comparable, but the polynomial optics technique is many times faster and comparatively to the cost of thin-lens calculations.” Pelgrims mentions.
One drawback to the method that POTA uses is that it is not possible to change the focal length. “Think of POTA as a library of prime lenses instead.”
POTA is a free and open source plugin for Maya and Houdini on both MacOS and Windows platforms.