The 18-55 (or 55-300) at 55mm and the 55 prime will cover the same thing. The difference is at 55mm, the 18-55mm is at a maximum aperture of 5.6, the 55-300 is at a max. aperture of 4.5 and the 50 prime is at 1.8. Aperture is a measure of how much light is able to be let in by the lens and the smaller the number, the more light. The 55 prime lens will let in almost 5x as much light as the others which will allow it to work fairly well indoors WITHOUT a flash, getting some nice candids.