PolarPro’s new circular filter looks like half the glass is missing – but that’s part of the effect. The PolarPro Split 50 Filter is a split diopter that allows two different distances to both be in focus at the same time.
Split diopters are a category of filters that cover part of the frame with what’s essentially half a magnifying glass. Half of the filter is a diopter, which is a filter commonly used to turn non-macro lenses into close-up shooters.
