Article: Use fast lenses for low light.Wide aperture lenses can see more in the dark

Most lenses are designed to work under normal lighting conditions. In photographic terms, "normal" generally means outdoors. Normal lighting may work in overcast weather, shade of trees or buildings, or in brightly lit rooms with skylights and plenty windows, but the real world isn't always like that.

Article: "Normal" lens buying guide.Life begins at 50

If one way to overcome problems associated with low light is to shoot at a wide aperture, then you need a wide-aperture ("fast") lens. Most kit zoom lenses only open to around f/3.5 or f/4, and fast zooms that maintain a maximum aperture of f/2.8 throughout the zoom range cost a mint.