The Theia Technologies FMT3555 filter mount is designed to allow attachment of M55x0.75mm diameter filters to a variety of lenses in their range with a 35mm diameter front barrel. Typically wide angle varifocal lenses do not incorporate a filter thread since the front optic often protrudes when the lens is set to wide; furthermore attaching . However Theia’s mid and telephoto lenses don’t have that problem – the FMT3555 attaches to Theia 4-10, 6-10 and 2.3mm lenses. A special thinner version FMT3555S is available for Theia 12-50mm lenses.
The filter mount is attached to the lens by means of three sharp point grub screws and can be added to lenses to allow an external filter (such as band-pass or polarising filter) to be added to the system. Theia lenses are of a high quality and perfect for a wide range of imaging application.