I was following an old tutorial by Andrew from blender guru he was using blender 2.76, I am working on blender 2.8. Noticed this only appears when I have the bump node connected, am I missing something?
This is an issue with the geometry and the lighting.
- First of all, make sure your sphere object is actually set to Smooth. (right click on object - Shade Smooth).
- Then, if that doesn't solve it, try adding more subdivisions. Modifier tab - add a Subdivision modifier.
- Play around with the Size setting of your light. Size is, basically, how diffuse your light is. To use a real-world example, covering a strong flashlight with a thin sheet will increase its "Size" (in Blender terms). In my experience, this artifact is most prominent when using strong lights with small size.