Assertion: eyepiece | /r/CapableOf | work at f-numbers
Facets:
value: well
type: DEGREE
Source sentences:
text: It is harder to make eyepieces that work well at fast f-numbers (that is, at small f-numbers) than at slow ones.
text: Thus it is no surprise that eyepieces that work well at fast f-numbers are fancier and more costly than ones that don't.