Photographic filter is an attachment that will allow certain kinds of light to be able to pass through, and able to reduce or block out other unwanted light sources.In short, the term filter really means anything that modifies the incoming light in some way and includes: polarizing screens, multi-image prisms,close-up attachments, soft focus filters, neutral density (ND) filters, grad... http://luxace1.net?partner_id=new_to241222