18-55 Vs 70-300. Now i mainly use my 17 50 with my 70 300 and i m happy. You mention it as 75 300 and 70 300.
I guess you are pretty new to photography since you are asking such a question. The 70 300 vr is a different lens for a different purpose. Compared for sharpness they are about the same at 105mm the 70 300 is a little better at 200mm and the 18 300 is a little better at 300mm.
The newer 70 300 is a good mid range lens for about 500.
Maybe 18 55 and 70 300. The benefits of this are. First you need to know that human eye has a focal equivale. I can always crop a little.
