Performing a complete in situ mechanical property analysis of polycrystalline thin films using X-ray diffraction is time consuming with most standard diffraction beamlines at synchrotron facilities and not realistic with laboratory diffractometers. Two-dimensional detection is shown to enable relatively fast and reliable X-ray strain measurements during in situ tensile testing of gold films deposited on polyimide substrates. Advantages and drawbacks in the use of two-dimensional detectors for this type of analysis are discussed for two commonly used geometries: reflection and transmission. (C) 2008 International Union of Crystallography Printed in Singapore - all rights reserved