Chapter 3: Choosing the Optimum HST Instrument 3.1 Overview 3.2 Choosing Between Instruments 3.3 Comparison of WFC3 with Other HST Imaging Instruments 3.3.1 Wavelength Coverage 3.3.2 Field of View 3.3.3 Detector Performance 3.3.4 System Throughputs and Discovery Efficiencies