... as bright field, dark field, phase contrast, photography, fluorescence, biological polarization and television etc. Specifications Optional Accessories ... Abbe NA=1.25 with Iris Diaphragm and Filter Holder Illumination 6V20W T-H Lamp with Adjustable ... Turret Annular, Phase Contrast Condenser, Centering Telescope, Green Filter Field Diaphragm Collector with Field Diaphragm Polarization Attachments Simple ...