FieldScout CM1000 NDVI Portable Chlorophyll Meter (Normalized Diff. Vegetation Index)

-Measurement Sample: Plant leaves, turf grass canopy
-Measurement System: Reflectance of 660 nm and 840 nm light
-Measurement Area: Conical viewing area between 12 and 72 in
-Minimum Distance: 12 in (30.5 cm) from lens
-Maximum Distance: Accuracy is unknown beyond 72 in from lens
    Distance From Lens:    Sample Area (Diameter):    
    12 in (30.5 cm)             0.53 in (1.35 cm)
    18 in (45.7 cm)             1.21 in (3.07 cm)
    48 in (1.22 m)               4.65 in (11.8 cm)

-Receptor: (4) photodiodes: (2) for ambient light and (2) for reflected light from the sample (leaf, turf)
-Measurement Units: NDVI (Normalized Difference Vegetation Index on a scale of -1 to 1
-Measurement Interval: 2 seconds per measurement
-Repeatability: ±5% of reading

Data Logger: Requires software and PC interface cable;
Capacity:
1,350 measurements with GPS/DGPS;
3,250 measurements without GPS/DGPS
-nonvolatile memory
Battery/Life: 2 AAA batteries (included); approx. 3,000 measurements