On 26/5/09, Miserere, discombobulated, unleashed: >Regarding an f/1.0 lens from Pentax: The 50mm f/1.4 has a rear element >~29mm in diameter, giving it an area of 660.5 sq.mm. The 50mm f/1.2 >has a rear element diameter of ~35.5mm, giving it an area of 989.8 >sq.mm. These numbers make sense: f/1.2 is 1/2 stop faster than f/1.4, >so the area of its rear element should be 1.5 times larger; and it is. > >A 50mm f/1.0 lens would have a rear element twice the area of the >f/1.4, which would mean its diameter would have to be square root of 2 >larger. That gives us ~41mm. Take any K mount lens and measure that >width; you'll see that the aperture lever would have to be removed in >order to have a rear element that large and the glass would be very >near the edge of the mount.
I'll meet your two paras and raise you whatever Adam maas says. -- Cheers, Cotty ___/\__ || (O) | People, Places, Pastiche ||=====| http://www.cottysnaps.com _____________________________ -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
