As in everything, especially in the photo, we are faced with compromises. Here, the very low prices for this type of focal result of several factors: lack of electronic, fixed aperture, simple structure. In short, we get for a low price optics for advanced amateurs, or all serious cases that can not afford a Canon 500mm f / 4 or other whose price is greater than 20x faster. That said, "for lovers" does not mean you will not get quality images!