On 23/12/06, J. C. O'Connell <[EMAIL PROTECTED]> wrote: > Basic trigonometry. God, even the numbers > are the easiest possible to calculate > (dont even need a calculator for that > baby). You need a 90 degree > lens horizontally to just cover > the object. The way to calculate f.l. > is to use same ratios of film/sensor size > to focal length as object size to object > distance. Since your object distance is > half the object size, your focal length > needs to be half the sensor horizontal size > which means a 18mm lens for FF 35mm film or > a 12mm lens for APS digital. Even wider f.l. > for slightly more coverage than the object itself.
Try again. A 12mm lens on APS format at 6' from the subject will provide a resultant horizontal field of view of 15' -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
