Many small unmanned aerial systems use true-color digital cameras for remote sensing. For some cameras, only the red channel is sensitive to near-infrared (NIR) light. Given a camera with this spectral capability, we modified it to obtain NIR-green-blue images. One advantage of this low-cost system is that images can be inspected directly from the camera. This camera was flown in a Piper Cub aircraft for estimating biomass of wheat and barley planted as winter cover crops. There was much greater variation in biomass within experimental strips than among strips, so correlations were not high. This research demonstrates the need to develop better calibration methods so inexpensive camera sensors can be used in precision agriculture.