The TIRF technique is a special kind of wide-field fluorescence technique for measuring cellsor SMC in an evanescent field without haze. By total reflection of the exciting light (typicallylaser) at the coverslip / medium interface, the fluorescence excitation is limited to a very thin space in the vicinity of the glass surface. The resulting fluorescence images exhibit extremely high contrast and resolution with the possibility of realtime imaging of cell membrane or labelled single molecules SMC. The VisiTIRF Fluorescence Imaging System from Visitron Systems is the ideal solution forthe analysis of finest structures or surfaces. The flexibility of the VisiTIRF system and the use of scientific digital CCD camera systems with optimal resolution, speed and sensitivity allows the adaptation of customized application and configuration. For fluorescence illumination we use different solid state laser or laser diodes. The coupling of the laser into the microscope is achieved by a flexible optical fibre. Our special own developed VisiTIRF condenser allows an easy adjustment of the laser beam to the correct illumination angle in the high aperture of the TIRF objective. A second optical fibre input allows the combination of TIRF and epi-fluorescence without moving any parts of the condenser. For epi fluorescence illumination we offer a standard HBO / HXP lamp or our VisiChrome polychromator system.