I just bought the D3200 kit 3 weeks ago which has 2 kit lenses. I was thinking about buying a prime lens (50mm f/1.8G AF-s). I went to a camera store and they were suggesting I should get the 50mm f/1.8D AF. As far as me being a beginner photographer, I believe that the AF lens only allows manual focus. Also, is it worth to invest on a 50mm f/1.8G AF-S lens?