diff --git a/Source/Core/VideoCommon/Src/PixelShaderManager.cpp b/Source/Core/VideoCommon/Src/PixelShaderManager.cpp
index 1d7478c018..4ec14ea948 100644
--- a/Source/Core/VideoCommon/Src/PixelShaderManager.cpp
+++ b/Source/Core/VideoCommon/Src/PixelShaderManager.cpp
@@ -206,7 +206,7 @@ void PixelShaderManager::SetConstants()
 	{
 		if(!g_ActiveConfig.bDisableFog)
 		{
-			float a = bpmem.fog.a.GetA() * ((float)(1 << bpmem.fog.b_shift));
+			float a = bpmem.fog.a.GetA() * ((float)(1 << (bpmem.fog.b_shift - 1)));
 			float b = ((float)bpmem.fog.b_magnitude / 8388638) * ((float)(1 << (bpmem.fog.b_shift - 1)));
 			SetPSConstant4f(C_FOG + 1, a, b, bpmem.fog.c_proj_fsel.GetC(), 0);
 		}