A filter, to be disposed concentrically with an optical axis of an imaging lens, capable of accurately controlling light transmission variation characteristics and effectively providing an apodization effect or a peripheral light intensity correction effect. The filter includes opaque dots disposed according to a honeycomb arrangement from a central portion toward a peripheral portion so as to have, at least partially, a Gaussian distribution like dot density and is structured to satisfy Condition Expression (1) given below when a size of the dots is taken as d. 0.003 mm≦d≦0.010 mm  (1).