A digital camera (400) comprises a sensor array (410) having image pixels (I) for capturing image data during an exposure period (EP), and focus-detection pixels (F) for determining focus information in a first mode of operation. The digital camera (400) is adapted for obtaining brightness related data (v) from the focus-detection pixels (F) in a second mode of operation, during capturing of an image by means of the image pixels (I), the digital camera further comprising a controller (428) adapted for determining the exposure period (EP) based on the brightness related data (v) obtained from the focus-detection pixels (F). A corresponding method is also provided.