Quote - > Quote - I did some renders this evening with a white ball, (color 1) without any textures, with a single spotlight and IBL . Poserpro GC makes the diffuse shadows and highlights on the ball very hard, and I don't like that, but perhaps I'm doing something wrong.

 

   You're doing nothing wrong. This is how real light behaves. This is a real life sphere with a point light, and the line between light and shadow is very harsh. It only looks odd to us because we rarely see any object lit from a single direction, there is almost always indirect light in addition.

This falls into what TVTropes called "The Coconut Effect".  People are so used to not seeing that harsh line between really bright and black on images, TV, and film, where the lighting is arranged, manipulated, or rendered so as to show the entire object, that when they see a real image it looks wrong to them, even though it's actually right.