Assertion: lens's thickness | /r/HasProperty | multiple lens elements
Facets:
Source sentences:
text: When the thickness of the lens is not much smaller than S 1 and S 2 or there are multiple lens elements (a compound lens), one must instead measure from the object and image to the principal planes of the lens.
text: When the thickness of the lens is not much smaller than S 1 and S 2 or there are multiple lens elements (a compound lens), one must instead measure from the object and image to the principal planes of the lens.