Why do the Compact Primes have different T-stops?
Four out of seven lenses have the same T-stop of T2.1. Three lenses vary because they are based on the ZF still lens optical designs. The ZF lenses are recognized as being optically unsurpassed in the world of still photography; they have superb stray light suppression and a more three dimensional look than other professional still lenses. The Compact Primes take the very best of the ZF lenses and improve upon them, with tighter mechanical and optical tolerances. A more precise optical adjustment during manufacturing and a strict cine quality control is applied (e.g. measuring of the close focus range or the distance scale). A unique 14-blade iris, not present in the ZF design, ensures precisely repeatable iris settings, a pleasing bokeh and organic, perfectly circular out-of-focus highlights with the Compacts.
