BRONICA - Zenzanon S to PS Lenses

This comprehensive technical study by M. Vettore examines the significant evolution between Zenzanon S and PS lenses for Zenza Bronica SQ cameras. The document traces the transition from the S lens family (introduced October 1980) to the new PS family (1986), following the company's relocation to a state-of-the-art manufacturing facility equipped with advanced lens testing and assembly equipment. The article provides in-depth analysis of improvements across multiple dimensions: optical refinements featuring multicoated lens elements across different groups, critical mechanical redesigns of the shutter cocking transmission system (eliminating the notorious "Sloppy Lens Syndrome"), and aesthetic enhancements including elimination of barrel side screws. A detailed case study of the 150mm lens redesign illustrates the shift from a simple aluminum disk mechanism to a more rigid cylinder design running on dual ball bearings, complemented by internal light-absorbing coatings. The document features comprehensive specification tables comparing all S and PS lens models with complete technical data including apertures, minimum focus distances, filter sizes, dimensions, weights, and 35mm equivalencies, accompanied by detailed photographs of internal components and mechanical assemblies.