Embodiments are directed towards performing depth estimation within a digital camera system based on interpolation of inverse focus statistics. After an image is captured, various statistics or focus measure may be calculated using, for example, a high pass filter. Depth is estimated by interpolating the inverse of the statistics for three positions of focus for the image. The inverse of the statistics, St(n), may be 1/St(n), or 1/St2(n), or even 1/StZ(n), where Z≧1. Several approaches to interpolating the inverse values of the statistics to obtain a depth estimate are disclosed, including a general parabolic minimum approach, using a parabolic minimum within a progressive scheme, or within a continuous AF scheme. The depth estimate may then be used for a variety of applications, including automatic focusing, as well as converting 2D images to 3D images.