The attached image was created by placing a single VRayLightRect above a plane. All sampling is VRay default.
Maya 2018, V-Ray 3.60.01, Windows7
Hi,
This is actually a known issue of the V-Ray Frame buffer winch doesn’t apply any dithering to the rendered image. Saving the image to a 32 bit file and opening it in Nuke for an example will give you the right look of the render.
Or simply roll the mouse over the values, and you will see that while the Display shows banding, the values are continuous, not stepped.