An imaging system 10 for automatically capturing an image of a faint pattern of light emitted by a specimen comprises: an electronic image capture device 12, such as a camera having a CCD sensor； a light-tight enclosure 24 having within a platform 32 for mounting a light-emitting specimen 30 thereon within the field of view of the image capture device 12； and a computer 50, connected to at least the image capture device 12. The computer 50 is adapted to: estimate a maximum signal level that can be expected from the specimen 30 and calculate, based on said estimated maximum signal level, a peak signal level estimate (psle)； calculate an exposure time on the basis of the psle and a desired resolution for a captured image； and capture an image for the calculated exposure time. The desired resolution may a user-selected choice, balancing a need for quality of final image against the time required to capture it. An associated method is also disclosed. Multiple exposures may be combined in odder to arrive at a final captured image, which helps to reduce overall image capture time whilst maintaining reasonable quality final images.
