The LYTRO ILLUM camera uses what we call the refocusable range: all of the points that can be brought into relatively sharp focus after a picture is captured. Information on the refocusable range can be found in the ILLUM User Manual.
The refocusable range has two component ranges: the near refocusable range, which is closer to the camera, and the far refocusable range, which is further away. Each offers a spectrum of relative sharpness, depending on the depth at which the image is refocused.
The refocusable range with the lens zoomed to 100mm focal length and the optical focus
at approximately 42cm. Note the relative size of the refocusable range.
The brighter the shade of the blue or orange band, the sharper objects at that distance will appear when refocused. The brightest band in each component range is its peak — where objects will appear sharpest when refocusing.
The refocusable range varies widely, depending on the zoom and focus positions of the camera when a picture is captured.
Effective use of the refocusable range and the depth composition features on the LYTRO ILLUM is the key to creating extraordinary Living Pictures. To find out how to best use these tools, see https://support.lytro.com/hc/en-us/articles/203001344-LYTRO-ILLUM-Training-Videos-One-Stop-Shop