What Is an Apodization Element and How Is It Used When Taking Photographs?

The literal definition if apodization is ‘removing the foot’, in photography terms however the term relates to the process of altering the shape of light entering a lens. In simple terms an apodization (often refered to as an APO, APD or STF lens) is a type of neutral density filter which becomes thicker towards its edges. The gradual thickening of the element limits the amount of light allowed to transition the lens progressively towards the edges of the image area. This has the effect of smoothing the edges of out of focus objects within an image, creating beautifully soft Bokeh and an enhanced sense of depth.