Tiffen 6785C 67mm 85C Filter

Color conversion filter decreases color temperature and provides a warming effect. Filter factor of 1.3 requires a 0.3-stop increase in exposure. This filter is made using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass, grinding flat to a tolerance of 1/10,000th of an inch, and then mounting to precision metal rings.