Portable ballot counters using camera technology and manual paper feed are potentially more reliable and less expensive than scanner-based systems. We show that the spatial sampling rate, geometric linearity, point-spread function, and photometric transfer function of off-the shelf consumer cameras are acceptable for ballot imaging. However, scanner illumination is much more uniform than can be economically accomplished for variable size ballots. Therefore flat-field compensation must be designed into the image processing software. We illustrate the mechanical design of a prototype camera-based ballot reader based on our comparative observations.