From a practical point of view we would usually only recommend photon counting where light levels are very low e.g. in biological luminesecence experiments. For fluorescence spectrophotometry we believe that analogue detection using the integration method employed by our input amplifiers is simpler and more flexible, especially as light levels can vary greatly from one experiment to another. In order to support researchers who are measuring very small optical signals we do supply a photon counting headstage and module as part of our standard range. The photon counting components are completely compatible with the standard analogue system, allowing the possibility of having both facilities implemented within the same box. If your equipment includes photon counting then please refer to us for additional technical advice, as the set-up procedure can be more complex.