Please explain the Cycles Sampling options in 2.75

Support Lighting and Rendering
1

I’m not entirely clear on what the Cycles Sampling options mean in 2.75. Prior to this version, I would set the rendered samples to, say, 300. In 2.75, to get the same effect, it appears I have to set the rendered samples to 18, which gives me a total samples value of 324 AA.

What do these options mean? What is AA? Why can’t I set samples to 300, but only to either 289 or 324?

2

Are you perhaps in branched path tracing mode? Switch to regular path tracing to get a normal single value for samples; E.G. 300.

Branched path tracing allows you to select which type of rays get more focus such as glossy materials, but you have to know how to fine tune it to benefit.