1. 
   Focal plane
   Plane on which a given subject is brought to a sharp focus, where the film is positioned.
   Found op http://www.peterashbyhayter.co.uk/glossaryT-Z.html
   
   
2. 
   Focal plane
   When a lens brings light to a focus, the image produced by the lens lies on an imaginary plane, which is the same distance from the lens as the focal length
   Found op http://www.irpoyser.co.uk/glossary.php
   
   
3. 
   Focal Plane
   A surface upon which the image of all points in the field of view of an optical instrument is created. See also: Focus, Optic Axis.
   Found op http://www.diracdelta.co.uk/science/source/f/o/focal%20plane/source.html
   
   
4. 
   Focal plane
   The plane on which the image of a subject is brought to focus behind the lens. To produce a sharp picture, the lens must be focused so that this place coincides with the plane on which the film sits. Also called the film plane.
   Found op http://www.rodsmith.org.uk/photographic%20glossary/rods%20photographic%20gl
   
   
5. 
   Focal plane
   The plane on which the image of a subject is brought to focus behind the lens. To produce a sharp picture, the lens must be focused so that this place coincides with the plane on which the film sits. Also called the film plane
   Found op http://www.digitalexposure.ca/sub1.html
   
   
6. 
   focal plane
   The flat plane at right angles to the optical axis onto which a lens will focus an image. Curvature of field results in an extended image forming on a curved surface known as the focal surface. A focal plane scale is the relationship between angles on the sky, in arcseconds, and millimeters of size ...
   Found op http://www.daviddarling.info/encyclopedia/F/focal_plane.html
   
   
7. 
   Focal Plane
   The point directly behind the lens where the film is usually located for exposure. That which is being photographed at an infinite distance, comes into clear perspective at this juncture, the focal plane
   Found op http://www.allmovie.com/glossary/term/focal+plane
   
   

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