float4 s = float4(UV.x + n.x, UV.y + n.y, 0, focus);
float3 col = tex2Dlod(postTex, s).rgb;
This one does compile, but it doesn't seems to work correctly (doesn't get blurred)...
You are right there, 'tex2Dlod' is the corresponding function but the source image needs mipmaps to make a difference. It seems you are trying to blur a scene through its render target and render targets never have mipmaps.
