Roughness is wrong in linear. Here's a fix.

After the artist I'm working with complained about everything shining, I had to take a look. The problem was immediately obvious: roughness in linear color space (HDR, Deferred, SpecularStandard, but I haven't tested with other combinations) is getting compressed via a power function. Of course the first candidate function I'd try is gamma correction. Sure enough, preemptively applying degamma in the standard shader inputs for smoothness compensates for the later gamma that Unity applies (presumably on write to buffer?) and gives the correct results.

And the easiest way to see something is wrong is to go into deferred, linear. Now turn on the debug view for Specular. Go between gamma and linear. Nothing changes, right? Great. Now turn on the debug view for smoothness, and go between gamma and linear again. Whoops, so much for gamma space being "incorrect", right?

With a modified shader we can match Marmoset Toolbag perfectly (on linear in both, gamma was fine previously). I've included the shader, it's just for specular standard, since that's what we're currently using.

This is on Unity 5.0.2.

 

Nice catch, I wondered why the reflection of the sun on glasses were shinier than the sun on my skybox. I figured it was how hdr colors were encoded but I never looked into it.

 

Tried it out, confirmed to be like that in 5.1 as well.
The rendertexture expects diffuse/specular/roughness/emission written to it to be in gamma space, and only worldnormals in linear space.

 

If this is truly a bug you should report it to UT. Nice find.

 

I knew there was something wrong with the shininess, despite so many people insisting that it was "realistic". I agree you should submit this fix to Unity.

 

Any way to get this working for Metallic shader?

 

Just curious which line that changed?
nvm found it