focal plane
noun
: a plane that is perpendicular to the axis of a lens or mirror and passes through the focus
Example Sentences
Recent Examples on the Web Every night between December 2009 and March 2019 that the moon was not overly bright, the telescope tracked a patch of sky, and the fibers fed the light that fell onto the focal plane into two spectrographs. 
Kyle Dawson, Scientific American, 1 May 2021 One end of each cable was supported by an aluminum plate positioned at the focal plane of the telescope. Kyle Dawson, Scientific American, 1 May 2021 In confocal microscopy the focal plane is imaged with a single, intense point of light, centered between two cones of light that flood the rest of the sample. Jen Christiansen, Scientific American, 21 May 2013 The first-focal plane design lets the shooter take maximum advantage of the reference marks in the reticle. Will Brantley, Field & Stream, 21 Dec. 2020 While testing of the focal plane continues, the first images are a huge milestone. Ashley Strickland, CNN, 8 Sep. 2020 The camera’s focal plane, similar to the imaging sensor of a digital camera, is more than 2 feet wide and is made up of 189 individual sensors that each contribute 16 megapixels, reports Ashley Strickland for CNN. Alex Fox, Smithsonian Magazine, 10 Sep. 2020 Still, most new products in the riflescope category have traits that appeal to long-range shooters: first-focal plane reticles, tactical milling turrets, and ample adjustment ranges. Andrew Mckean, Outdoor Life, 20 Jan. 2020 The difference between focal planes becomes exaggerated at extremely close and far target distances—decreasing accuracy and obscuring the reticle. Michael R. Shea, Field & Stream, 3 Jan. 2020 See More
Kyle Dawson, Scientific American, 1 May 2021 One end of each cable was supported by an aluminum plate positioned at the focal plane of the telescope. Kyle Dawson, Scientific American, 1 May 2021 In confocal microscopy the focal plane is imaged with a single, intense point of light, centered between two cones of light that flood the rest of the sample. Jen Christiansen, Scientific American, 21 May 2013 The first-focal plane design lets the shooter take maximum advantage of the reference marks in the reticle. Will Brantley, Field & Stream, 21 Dec. 2020 While testing of the focal plane continues, the first images are a huge milestone. Ashley Strickland, CNN, 8 Sep. 2020 The camera’s focal plane, similar to the imaging sensor of a digital camera, is more than 2 feet wide and is made up of 189 individual sensors that each contribute 16 megapixels, reports Ashley Strickland for CNN. Alex Fox, Smithsonian Magazine, 10 Sep. 2020 Still, most new products in the riflescope category have traits that appeal to long-range shooters: first-focal plane reticles, tactical milling turrets, and ample adjustment ranges. Andrew Mckean, Outdoor Life, 20 Jan. 2020 The difference between focal planes becomes exaggerated at extremely close and far target distances—decreasing accuracy and obscuring the reticle. Michael R. Shea, Field & Stream, 3 Jan. 2020 See More Word History
First Known Use
1840, in the meaning defined above
Medical Definition
focal plane
noun
: a plane that is perpendicular to the axis of a lens or mirror and passes through the focus