Method for Observing Organisms and Associated System

A method for observing a sample, the sample comprising:

• a set of organisms
• a solid substrate supporting the set of organisms,
• the method being characterized in that the method includes the steps:
• illuminating at least one portion of the sample with a light beam,
• acquiring a first diffraction pattern corresponding to an image of waves from the diffraction of the light beam by a first portion of the set of organisms,
• acquiring a second diffraction pattern corresponding to an image of waves from the diffraction of the light beam by a second portion of the set of organisms,
• comparing the second diffraction pattern with the first diffraction pattern,
• determining at least one characteristic relating to the set of organisms from the result of the comparison step,
• the method comprising, during each acquisition step, a step for adapting the size of the light beam relatively to the size of the relevant portion of the set of organisms.