I will reply all your recent questions in this thread.

- The difference between 50mm 1.4D and 50mm 1.4G isn't very much. The latter has SWM (silent wave motor) so it is more silent than the previous one. Also, in optics and sharpness 1.4G beats its predecessor (although not by much). I'd recommend 1.4G with little doubts (because the autofocus speed in G is a little slower than D). Still 50mm 1.4G is what you should buy. Now if you want to save some money and buy that newly released 58mm 1.4G that nikon just released, be my guest, but it will cost more than your camera.

- Filter lenses are used for many reasons, and it depends on what kind of filters you are trying to buy. But if you are buying a 50mm 1.4G, you need to, without any doubt buy a 58mm UV filter the moment you purchase the lens. 58mm is the diameter of the lens, hence 58mm filter. This will not only protect your lens from UV rays but also from scratching and other damages. Remember, lens is but just a glass, if you drop it or scratch it, all your 500$ will flushed down the drain. Now there are many choices for 58mm UV filter as well, there is a high end filter from Singh Ray and a little less (but expensive) B+W, but I'd ask you to refrain buying from them. Get a Hoya filter, doesn't cost much and serves as good.

Also, there are other types of filters, warming filters, circular polarizing & linear polarizing filters and neutral density filters, and many others. For your 50mm 1.4G, you do not have to worry about any of these. Get back to me when you buy a wide angle lens in future and we can discuss the possibilities.

You spent 1200 on camera with no lens? I'd rather spend 1200 on lens with a cheap camera.

Behoove, I think I have heard of some words you have used :)

You are speaking of SWM Kiddo? Haha, that is a common jargon in photography.

But yes, like Kiddo mentioned, I wonder why you spent 1200 dollars on a camera. Considering you a neophyte photographer, I'd like to suggest the chepest Nikon DSLR in the market to start off, buy 50mm 1.4G, get a UV filter, and start saving for 24-70mm 2.8G. Remember, sooner or later you will replace your camera with a higher end one, but your lens will remain with you forever.

@behoove me,

Thank you for your effort to give detailed informations. I appreciate that.
50mm 1.4G sounds good. But, I am worried that being the only lens I am going to have and not being able to zoom in and out, it brings discomfort in taking pictures. Should I wait another month and save up to get the 24-70 f2.8 instead of the 50mm 1.4G? Also, I found a 77mm hoya circular polarizer for $47.20. The link is below:

http://www.bhphotovideo.com/c/product/22708-REG/Hoya_B77CRPL_77mm_Circular_Polarizer_Glass.html

Do you have any idea how good this circular polarizer is, especially for the price? Does it come close to B+W's model?

I don't have any experience with the ND filters, and I would want to get a good but inexpensive one (less than $100). Which type would you suggest to start with?

Cheap dslr's have many limitations so I ended up with d7100 (59 point AF system).

@kiddo,

Yeah I spent little too much on the camera. I did that coz I have been planning on getting good glass as well. a 24-70 f2.8 will definitely look better on a d7100 than it would on d3100.

Get Nikon 24-70 2.8...if u really are thinking abt waiting for a month and getting a better lens... It is the Best all purpose lens....

@xekin,

Thanks for your suggestions. I actually might buy a 24-70 now and wait sometime to buy the 50mm.