about texture environment with EXR files

[wisemanxxx]

I try render my exterior scene with a exr file.
I can't get a satisfied result, I change gamma value to 1 , scene illuminated but shadows are so smooth. If I try increase gamma value between 1 and 2 scene is completely black.when value is 2 very dark and sharp shadows but unsatisfied lighting. with HDR files I can set gamma value between 1 and 2 and set shadow's sharpening.
What is correct gamma value for a exr file? and suggestions?