On Tue, May 26, 2009 at 12:58 PM, Cotty <[email protected]> wrote: > 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 >
MARK! -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
