focus stacking ... capture a series of photos each with a different distance in focus then in post processing synthesize a single photo from the portions of each which is most in focus ... heavily used for microscope image capture where depth of field is minute ... another is high dynamic imaging ( HDR ) which is a similar bracketing of several exposures each with a different shutter speed of each image captures maximum detail in a different exposure level ... if you wish to combine both of these tricks into a single output image where you use say a bracket of 4 exposures for the focus stacking and say 5 for the hdr then total necessary photos would be 4 * 5 meaning 20 separate photos