The signal to noise (SNR) performance of selected linear array image sensors belonging to the CCD (charge coupled device), SSPDA (self scanning photodiode array), and PCD (plasma coupled device) families is analysed. Our purpose was to investigate image sensors for use in obtaining high resolution spectra of the upward and downward irradiance light fields in the ocean. Image sensors studied here, have practical dynamic ranges of the order of (10 super(4)). Given this, it is possible to work the sensors at a stabilised moderately cool temperature of 15 deg. C and to intelligently control the exposure time of the device, so as to reliably measure flux levels in the range 1 W/m super(2)/nm to 10/6 W/m super(2)/nm commonly encountered in the ocean. The simulated response of each sensor type to a known in-situ spectrum is computed in terms of SNR values so as to narrow down the choice of sensor(s) for use in in-water radiometry