Soft Reflections settings
You can enable soft reflection by setting ON the "Soft" property of the render options pannel. The "Quality" property determines the number of samples used to compute the soft reflections. The higher quality requirement is more critical for surfaces with very wide soft reflections. The soft reflection works by sending out multiple reflection rays so this can be CPU expensive especially for large specular sizes which requires more reflection rays than tight speculars. Soft reflections are limited to one level. This basically means that any secondary soft reflective surface will be treated as sharply reflective. This is to prevent exponential render times.
The sharpness to softness of each surface reflection is determined by the surface "Specularity size" property. A small specular size will produce tight soft reflections and sharper reflected images while a large specular size will produce wide soft reflections and blurrier reflected images.
Reflective sphere without soft reflection
With soft reflection and 5% for specular size
With soft reflection and 10% for specular size
With soft reflection and 50% for specular size
With soft reflection and 200% for specular size
With soft reflection and 400% for specular size
With soft reflection and 10000% for specular size