What size of object can I scan with an HDI 100 series scanner?
The single scan fixed field of view (FOV) can be found in the product datasheet (http://lmi3d.com/support/downloads/hdi-100-series).
Generally speaking, the HDI 109 can scan objects as small as a dental impression (roughly 2.5 x 3 inches) and as big as a small toy (3 x 4 inches) in a single shot. The HDI 120 can scan objects as small as a dental impression (roughly 2.5 x 3 inches), but with lower quality, and as big as a large shoe (6 x 7 inches) 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.