[Answer] What is the depth of field?

Answer: B. The area of sharpest focus in a photograph.

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What is the depth of field? For many cameras depth of field (DOF) is the distance between the nearest and the farthest objects that are in acceptably sharp focus in an image. The depth of field can be calculated based on focal length distance to subject the acceptable circle of confusion size and aperture. A particular depth of field may be chosen for technical or artistic purposes. Limitations of depth of field can sometimes be overcome with various techniques/equipment. For many cameras depth of field (DOF) is the distance between the nearest and the farthest objects that are in acceptably sharp focus in an image. The depth of field can be calculated based on focal length distance to subject the acceptable circle of confusion size and aperture. A particular depth of field may be chosen for technical or artistic purposes. Limitations of depth of field can sometimes be overcome with various techniques/equipment. For cameras that can only focus on one object distance at a time depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus. "Acceptably sharp focus" is defined using a property called the circle of confusion . For cameras that can only focus on one object distance at a time depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus. "Acceptably sharp focus" is defined using a property called the circle of confusion . The depth of field can be determined by focal length distance to subject the acceptable circle of confusion size and aperture. The approximate depth of field can be given by: ${\displaystyle {\text{DOF}}\approx {\frac {2u^{2}Nc}{f^{2}}}}$ for a given circle of confusion (c) focal length (f) f-number (N) and distance to subject (u). As distance or the size of the acceptable circle of confusion increases the depth of field increases; however increasing the size of the aperture or increasing the focal length reduces the depth of field....

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