https://i.ytimg.com/vi/NhOdnOow6DY/hqdefault.jpg http://www.blenderhd.com/ All of Blender Cycles’ sampling and light path settings explained in one video. Aimed at beginners, but helpful for anyone. Topics include: sampling, clamp values, path and branched path tracing, volume step size and max steps, min and max bounces, transparency, and much more! source