Lenses are optimised to work within certain limits. Stretch the limits and quality will suffer, or they get heavier and more expensive. This is why the very expensive zoom lenses cover a fairly short range at shorter focal lengths eg 16-35, 17-40 and gradually the range increases - 24-70, 70-200, 100-300, 100-400 and so on. Swapping lenses to suit your photography is one of the things that makes an slr special.