Zoom Blur

This transformation creates a blurred version of the current image that simulates zooming the lens while taking a time exposure. This effect differs a little from what you get using a zoom lens since smaller versions of the input image have a wider field of view and are thus truncated, while larger versions are less sharp than the original.

Zoom Blur displays a small cross overlayed on the input image to show the center of the zoom. By default this control point located at the center of the input image, but you can drag it to any location you wish.

Amount

The amount control lets you control how much of the blur transformation is applied to the input image. You can apply a percentage of the transformation to the entire image, or you can specify an amount mask to restrict the effects of the transformation to only part of the input image.

Blur

This slider lets you choose the degree of blurring - larger values zoom more and smaller values zoom less.

Step Size

This slider controls how smooth the blurring is - at 0% it is very smooth and as you increase the step size the zoom is done in regular steps.