The single scan adjustable field of view (FOV) can be found in the product datasheet 

Generally speaking, the HDI Advance can scan objects as small as a leaf (roughly 3 x 3 inches) and as big as a person's entire body in a single shot.

However, larger objects can be scanned by taking multiple scans and stitching the data together using one of several techniques.

If the object you want to scan is more than 8x to 10x larger than the maximum FOV, you probably want to consider a different scanner. You can still scan the object, but it will mean a lot of work.

On the other end of the scale, if your object is less than 1/3 the size of the smallest FOV, you are likely not to pick up as much detail as you would want to see in the scan.