Archived posting to the Leica Users Group, 1998/12/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]As I said, below, "this is not an exact ratio" and I was stating a "simple rule of thumb". But your continuance, putting more accuracy into it, will indeed help LUGgers understand DOF. Thanks Henning, Jim At 08:30 PM 12/7/98 -0800, you wrote: >Jim Brick wrote: > >>By the way, DOF extends farther behind the point of focus than in front. >>The rule of thumb is 1/3 forward, 2/3 back, from the exact point of focus. >>This is not an exact ratio, but when photographing it's very very close. >>Consult the scales on your lens to see this. > >This applies only at certain distances. Obviously, if you focus at the >hyperfocal distance (hyperfocal being determined by whatever DOF criteria >you set) or further, DOF extends an infinite amount behind the subject, but >a finite distance in front. > >If you are shooting at 1:1, DOF extends exactly as far behind as in front. > >That leaves a whole lot of other distances, which we normally shoot at, so >called middle distances, at which the 1/3, 2/3 rule gives an approximation. > > > * Henning J. Wulff > /|\ Wulff Photography & Design > /###\ mailto:henningw@archiphoto.com > |[ ]| http://www.archiphoto.com >