Catalyzes the formation of the (+)-camphor precursor (+)-bornyl diphosphate from geranyl diphosphate. The enzyme also produces significant amounts of (+)-alpha-pinene, (+)-camphene, and (+-)-limonene. (2E)-geranyl diphosphate = (2S,4R)-bornyl diphosphate (2E)-geranyl diphosphate = (1R,4S)-camphene + diphosphate (2E)-geranyl diphosphate = (1R,5R)-alpha-pinene + diphosphate Binds 3 Mg(2+) ions per subunit. Terpene metabolism; (R)-camphor biosynthesis. Homodimer. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.