Assertion: polarising filter | /r/AtLocation | front of the camera lens
Facets:
value: in order to darken skies
type: PURPOSE
value: often
type: TEMPORAL
Source sentences:
text: A polarizing filter or polarising filter (see spelling differences) is often placed in front of the camera lens in photography in order to darken skies, manage reflections, or suppress glare from the surface of lakes or the sea.