Figure 3-22 Achromatic Lens (a) By using two differently shaped lenses (often of different types of glass), light of different wavelengths can be brought into focus at the same focal length. Such achromatic lenses are used in cameras and many telescopes. (b) Same object as in Figure 3-21b imaged through an achromatic lens. Note that the colors on the edges of the petals seen in Figure 3-21b do not occur here.