For distances between approximately 1900mm and 2400mm, it is recommended to print the A2 marker pattern scaled at 125%. At distances of more than 2400mm it is recommended to scale the marker pattern at 150%.
Hence, the recommend solution is to decrease the working distance between photoneo 3D scanner and marker pattern.
For calibration step, follow the link attached. Link: http://wiki.photoneo.com/index.php/Scans_alignment