A relatively low‐cost digital measurement system configured with off‐the shelf components (a standard consumer High 8‐mm camcorder, video cassette recorder, video monitor, desktop computer with image capture board, and image analysis software) has been used in applications from benchtop stem length and leaf area measurements to aerial imaging for precision agriculture applications. However, preliminary research identified a systematic error in estimating leaf area using this system, which further investigation revealed to be caused by the internal calibration method used. Further research was needed to determine appropriate calibration methods for length and area measurements using this system. Length measurements were very accurate and repeatable using a vertical (i.e., parallel to the axis of objects) two‐point calibration. Two‐point (vertical, horizontal or diagonal) calibration led to over‐ or under‐estimation of area, but three‐point calibration yielded very accurate measurements of area and percent coverage. This system proved to be a versatile and useful method of measuring many plant size parameters.