Pointing out relevant information to a user is one application of focus+context techniques in information visualization. We present a method for doing this which uses selective blur to direct the user’s attention. This method is based on the depth of field (DOF) effect used in photography and cinematography, and is therefore both familiar to users and perceptually effective. Because this method blurs objects based on their relevance rather than their distance, we call it Semantic Depth of Field (SDOF). We also present four example applications that use SDOF to show its usefulness in practice, and also provide details of a fast implementation that makes it possible to use blur in interactive applications. A short report on the results of a user study we performed is also given.