Assertion: diaphragm | /r/CapableOf | allow on the contrary
Facets:
Source sentences:
text: The stop reduces the lens to its central aperture; the diaphragm, on the contrary, allows all the segments of the lens to act, but only on the different radiating points placed symmetrically and concentrically in relation to the axis of the lens, or of the system of lenses (of which the axis is, besides, in every case common).