Assertion: aperture | /r/CapableOf | allow that of f/4
Facets:
value: for exposure
type: PURPOSE
Source sentences:
text: The aperture is proportional to the square root of the light admitted, and thus inversely proportional to the square root of required exposure time, such that an aperture of f/2 allows for exposure times one quarter that of f/4.
text: The aperture is proportional to the square root of accepted light, and thus inversely proportional to the square root of required exposure time, such that an aperture of f/2 allows for exposure times one quarter that of f/4.