objective lens vs lens system

objective lens and lens system both are nouns.

Word	Noun	Adjective	Verb	Adverb
objective lens	Yes	No	No	No
lens system	Yes	No	No	No

As nouns, lens system is a hypernym of objective lens; that is, lens system is a word with a broader meaning than objective lens:

objective lens: the lens or system of lenses in a telescope or microscope that is nearest the object being viewed
lens system: a transparent optical device used to converge or diverge transmitted light and to form images

Other hypernyms of objective lens include lens, lense.

objective lens (noun)	lens system (noun)
the lens or system of lenses in a telescope or microscope that is nearest the object being viewed	a transparent optical device used to converge or diverge transmitted light and to form images