Just bought a Nikon D3300 with supplied AF-S DX Nikkor 18-55mm f/3.5- 5.6G VR ll lens. I'm interested (at the present) in portraits, but cannot get this lens to blur backgrounds. I have used Aperture priority at its widest, and ISO 100. Am I doing something wrong? I think I need to go for a larger aperture lens, but I desperately need independent help in choosing. My budget would be in the £200 area. I am a novice at this photography thing! Thanks in advance.