Taylor Hobson T-P COOKE Anastigmat 5 inch f/4.5 Brass Lens + Flange 217064

Physical build: Housed in a heavy brass barrel (often featuring an internal iris diaphragm) typical of early-to-mid 1900s production by Taylor, Taylor & Hobson. Aperture: An f/4.5 max opening was considered very fast for early 20th-century large/press format lenses, letting them function in dull lighting conditions.