Archived posting to the Leica Users Group, 2001/02/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]DOF is objective. It is based on a perfect lens in which a mathematical point in the plane of focus is projected as a mathematical point on the image. Nearer or farther than the plane of focus, a point will appear (roughly) as a circle rather than a point. The maximum acceptable diameter of this circle is chosen as the circle of confusion for DOF computations, which are based on theoretical optical considerations. I believe Zeiss uses 0.025mm and Leica 0.033mm for the COC in the computations for their DOF scales. It is all theoretical, based on a perfect lens, and has nothing to do with the resolution of a specific lens. Richard