sentences:  A "slow" lens (one that is not capable of passing a lot of light through) might have a maximum aperture from 5.6 to 11, while a "fast" lens (one that can pass more light through) might have a maximum aperture from 1 to 4.Fast lenses are by definition larger than slow lenses (for comparable focal length), and typically cost more.The aperture affects not only the amount of light that passes through the lens, but also the depth of field of the resulting image