No trig. is needed for this kind of calculation. If you know object size and distance, then all you need to know is that the object distance/object size = focal length/sensor size. Solving the equation, focal length needed = (object distance/object size) * (sensor size in mm) jco
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of David Savage Sent: Saturday, December 23, 2006 9:28 PM To: Pentax-Discuss Mail List Subject: Re: Determining a Focal Length On 12/24/06, P. J. Alling <[EMAIL PROTECTED]> wrote: > I think you need the angle of view more than field of view. the > formula for AOV is > > AOF = 2*tan^(-1)/(F/2*f) where F is the size of the sensor f is the > focal length. You'll have to use some algebra to rearrange the terms > to solve for "f". I'm just feeling too lazy... f = B / (2xtan(AOF / 2)) I got it from here: <http://www.mhohner.de/formulas.php> Dave (also too lazy to work it out) -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
