Need to know what the lens is you're pulling from your Peli? Need to know the filter size before you grab that lens? Need to know the minimum focus and the maximum magnification? What about a quick reference of the lens weight while you're packing that carry-on?
Each rear lens cap includes the focal length, the minimum aperture, the minimum focus, the maximum magnification, the filter size, and the weight. Some extra specs are also included; like if it's a G, G Master, has OSS.
Theses caps are for the Full Frame lenses manufactured by Sony.
