The 50mm prime lens is the only lens a beginner needs for portraits, and I'll die on that hill. I've shot weddings, street scenes, and headshots with a cheap 50mm f/1.8, and the images look natural because you have to move your feet—not just zoom like a lazy photographer. Zoom lenses are convenient for travel, sure, but for learning composition and depth of field, the 50mm forces you to think. I've seen stunning portraits taken with an 85mm, but that costs three times as much. For under $200, the 50mm delivers sharpness and bokeh that beats any kit lens. If you can't create a good portrait with a 50mm, upgrading your gear won't save you.