low light levels and where excitation energy must be kept to a minimum to reduce photon damage and bleaching of the sample and fluorophores the electronic image acquired by imaging means 106 is provided to a control unit 128 which can contain automatic gain controls white balance black balance and auto iris functions all of which can be controlled or limited by the operator of the system for maximum imaging control and flexibility a particular advantage of this system is the use of a video camera with the ability to display fields of image versus frames when only the odd or even fields are displayed and the interlace information is interpolated from the adjacent fields then effective frame speeds equal to the field rate can be achieved this is important when it is desired to study very high speed motion with a minimum of motion during the image acquisition time it is also useful to use electronic shuttering to limit the motion during a field duration the electronic signal from imaging means 106 and control unit 128 is then provided to image inverter system 132 which electronically converts it to obtain either the luminance chrominance or luminance and chrominance negative image of the image provided to it from control unit 128 a trivial example of the function.