Ideally, the lens aperture should be f/2.8 or greater. Many zoom lenses have a fixed aperture of f/2.8, such as the 16-35mm f/2.8 or 24-70mm f/2.8. Although they are pricey, they are well worth the extra cost due to their flexible zoom range and their ability to shoot at f/2.8, which is ideal for shooting in low light.