What the hell is this lens filter? I just spent 1200 on a camera and it didn't have a lens. I barely have cash to buy a good lens. Then this filter thing comes up. What is this filter and what does it do? I am looking to buy a 50mm nikkor 1.4D or 1.4G. What kind of filter does it need and what does it do? I am basically looking to take pictures indoors and outdoors; regular family pics, nothing fancy.