Large lens apertures will be required in dull light. The image below was taken inside a building in very dull lighting conditions, in these situations large lens apertures of f/1.4 to f/2.0 will be required. The larger the lens aperture the more light is received at the film or image sensor. Also large apertures may be required if you need to use higher shutter speeds.
Large aperture lenses will cost significantly more than smaller aperture lenses however they will offer a great advantage in low light conditions.
Many of the latest digital cameras have a big advantage when photographing in low light as theynow have extremely high ISO capability comparted to a few years ago when we used film. Many digital cameras have a capability of up to ISO3,200 or ISO6,400, which gives a big advantage in low light.