Recently, 2D detectors, such as IP (imaging plate) or CCD (chargecoupled device), become popular in single crystal data acquisition. As a practical guide, basic information is discussed on diffraction geometry and data processing of 2D detectors, in comparison with those of four-circle diffractometers. Main topics are a typical flow in data collection, indexing, evaluation of spot positions, data collection strategy, evaluation of integrated intensities, Lorentz factor, and determination of precise cell parameters.
