Petzval
/ˈpɛtsvɑːl/ /ˈpɛtsv(ə)l/Optics and Photography
noun
Used attributive with reference to various concepts related to a lens system designed by Petzval; specifically Petzval condition noun the condition for freedom from astigmatism of a compound lens, that the sum of the ratios of the power of each element to its refractive index be zero. Petzval lens noun a lens consisting of two widely spaced colour-corrected compound lenses whose negative elements are on the inner sides. Petzval sum noun a number representing the degree of curvature of the field of a compound lens, derived from the refractive indices and surface radii of its elements.
Origin
Late 19th century; earliest use found in William de Wiveleslie Abney (1843–1920), civil servant and photographic scientist. From the name of József M. Petzval, Hungarian mathematician.
- paddle-board
- paddle boat
- paddle-box
- paddle-box boat
- paddle brush
- paddle crab
- paddlefish
- paddle-foot
- paddle-like
- paddle one's own canoe
- paddle-plane
- paddle pop
- paddler
- paddle shaft
- paddle steamer
- paddle tennis
- paddle wheel
- paddlewheeler
- paddlewood
- paddling
- paddling pool
- paddo
- paddock
- paddock bomb
- paddock course