Dear friends: My previous posting on DOF and DOF preview included a formula for hiperfocal distances. I apologize because the formula had a typo. IT SHOULD SAY: For 35mm cameras: hiperfocal distance (in mm) = (focal dist. of lens)2/(0.033*Aperture) This is, (the square of focal distance of the lens)/ (diameter of the circle of confusion times the aperture) Saludos desde Chile Alfredo