このカメラはだれのものですか。

this (something or someone close to the speaker (including the speaker), or ideas expressed by the speaker)

camera

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

who

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

thing; object; article; stuff; substance; one's things; possessions; property; belongings; things; something; anything; everything; nothing; quality; reason; the way of things; used to emphasize emotion, judgment, etc.; used to indicate a common occurrence in the past (after a verb in past tense); used to indicate a general tendency; used to indicate something that should happen; item classified as ...; item related to ...; work of ...; cause of ...; cause for ...; somehow; somewhat; for some reason; really; truly

be; is

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way