The UV & IR Cut Filter from Hoya is a lens filter that when attached to your lens permits only the visible spectrum of light rays to enter the camera & get captured by the sensor. It blocks out both the higher frequency ultraviolet rays & lower frequency infrared light rays. This is important to digital photographers because the CCD & CMOS sensors found in our cameras are extremely susceptible to catching UV & IR rays just outside the visible spectrum that have a very negative impact on image quality. The filter offers even greater versatility than is already found in a combination UV-IR filter due to its front & rear threads. They permit stackable standard-size filters to be attached giving you even more filter effect options while also accommodating a standard lens cap as well. Another benefit to using the UV-IR filter is that it can also reduce the effects of atmospheric haze to a greater degree than would be found with a standard UV filter. This means that sharper images with more depth & finer richer color gradations are possible when utilizing the filters effects in your photography. This combination filter is a very convenient option for those who seek a clearer & sharper image when captured outdoors while getting the benefits of two filters in one.