I agree with JKeller. The top image looks like there's a fog or haze layer applied. And the bottom looks crisper. Depending on what look you're going for will determine which one is the better render. Also try rendering sections the scene at 300 dpi and larger pixel with and height so you can see more detail and how the blur is trully affecting the image. The images above are small and hard to really tell that a blur has been applied, it looks more like an atmospheric filter than a blur. James