Assertion: close lens | /r/ObjectUse | used in combination
Facets:
Source sentences:
text: Several close-up lenses may be used in combination; the optical power of the combination is the sum of the optical powers of the component lenses.
text: Several close-up lenses may be used in combination; the optical power of the combination is the sum of the optical powers of the component lenses; a set of lenses of +1, +2, and +4 diopters can be combined to provide a range from +1 to +7 in steps of one.