Yes, this filter has full brass front and rear threading for smooth attachment and stacking. Our ND filter is compatible with all standard lens filters as well as our Infrared lens filters.
Yes! This filter is engineered to be used for visible light photography with no vignetting or color tinting. It also has the most effective IR neutral darkening we’ve produced to date, making it the ideal ND for Infrared long exposures and video work.
The refractive index is dependent on the material, and is a measurement of the amount that that material will refract or “bend” light as it passes through. At 90 degrees or dead center of the filter the light does not deflect and continues straight, but as the angle of incidence towards the edge of the filter increases, it deflects light more and more causing a discrepancy across your frame, particularly with wide angle shooting. The higher the refractive index value, the more image quality can suffer.