Ultraviolet photography sensor will pick up reflected infrared radiation as well as ultraviolet, which may obscure the details that would be resolved by ultraviolet alone. Most types of glass will allow longwave UV to pass, but absorb all the other UV wavelengths, usually from about 350 nm and below. For UV photography it is necessary to use specially developed lenses having elements made from fused quartz or quartz and fluorite. Lenses based purely on quartz show a distinct focus shift between visible and UV light, whereas the fluorite/quartz lenses can be fully corrected between visible and ultraviolet light without focus shift. Examples
Ultraviolet (Light My Way) singing the repeated "baby"s, one of the most heavily used clichés in pop songs and one that he had avoided up to that point in his songwriting; Flood later commented that "he got away with it alright." Although the song is ostensibly about love and dependency, like many U2 songs, it also lends itself to religious interpretations. Listeners have heard an allusion to the Book of Job and its tale of God serving as a lamp upon Job's head walking through the darkness. Robyn Brothers suggests that ultraviolet light is "a metaphor for a divine force both unseen to the