Photomicrography and telephotography
Roster experimented with the technique of photomicrography, producing images of tiny insects, botanical and anatomical specimens, etc. He presented examples of his work, first at the Italian Photographic Exhibition held in Florence in 1887. On this and other occasions—Brussels (1891), Antwerp (1892), Hamburg (1893), and Milan (1894)—his images were greatly praised. At the 1887 exhibition he received also an award for his snapshots of the dome of Florence’s cathedral, taken with a telephoto camera lens of his own invention. His experiments with telephotography were primarily aimed at perfecting the technical and operational aspects of taking pictures rather than for scientific purposes.