The present invention relates to a method and system of array imaging that extends or maximizes the longevity of the sensor array by minimizing the effects of photobleaching. The imaging system has a light source, a variable exposure aperture, and a variable filter system. The system extends the longevity of sensors by (1) using the variable exposure aperture to selectively expose sections of the sensor array containing representative numbers of each type of sensor, and/or (2) using the variable filter system to control the intensity of the excitation light, providing only the intensity required to induce the appropriate excitation and increasing that intensity over time as necessary to counteract the effects of photobleaching.