Variable Gaussian filter allows you to control the blur power within the frame. You could have the Blur effect appear only where your subject is rather than over the entire image for example, or keep the Blur effect in outer areas to softly frame your subject. Parameters: Size Controls the blur power. Value of 1.0 sets the maximum blur, but you can enter in edit field values up to 4.0 and get more blur, but with a slightly reduced quality. Round This option selects the mask shape. If On - the mask is round, otherwise - the mask uses frame aspect. Distribution How the blur size vary over the frame. Values over 0.5 add more blur at frame edge, values under 0.5 - at the frame center. Center X, Y Controls the position of the mask center point. By keyframing the Center control you can have the effect area track your subject's movement (Distribution values under 0.5 here). See also Gaussian Blur variations: Gaussian Blur - Blur an image. Gaussian Blend - Blur an image and blend with the original.