HDR vs EXR Lighting Setup - Frustrated!

[Wrender]

Hi Guys! Here's the problem:

 

I've set up a scene using 3DS Max/Mental Ray with a MR Sun and Skylight using a EXR/HDR in the Environment slot.

 

When I use an EXR file everything is fantastic. I'm able to lower the output amount down in the material editor, adjust the physical scale to unitless, and get the exposure value set. Rendering looks great!

 

HOWEVER, I would like to do this same thing with an HDR file. In my case above I'm using the exact same image but in a HDR format. I would think you would pop it in and the settings would be the same. But when I do this, lowering the output amount makes the image dull and desaturated, rather than just bringing the intensity down as in the exr file. So when I render, I just get a muddy grey sky and background image....why why why?

 

If anybody could shed some light (punny right?) on the issue I would appreciate it!

 

Thanks,

Ryan