359 / | HD | OPTICS: SYSTEMS (INCLUDING COMMUNICATION) AND ELEMENTS |
885 | ABSORPTION FILTER {7} | |
886 | DF | .~> Fluid |
887 | DF | .~> Sequentially additive |
888 | DF | .~> Neutral or graded density |
889 | DF | .~> Movable in or out of optical path |
890 | DF | .~> Superimposed or series |
891 | DF | .~> Filters in optical parallel (e.g., colors side-by-side, etc.) |
892 | DF | .~> With support or frame |