I made simple scene with 1 sphere and 1 sun light. I set strength of sun lamp to 1.000 (emission node) and add diffuse BSDF surface with white(R1G1B1) to sphere. When I render this scene, sphere shows gray color(max 0.3) even at completly orthogonal with sun direction.
I think diffuse surface reflect light using lambertian, so surface shows white color at orthogonal point.
What's wrong in my scene?
(I used Cycles renderer and cut off shadow)