I find myself using the Radial Blur quite a bit. It can create some intense effects by creating blurs around a point, simulating the result of a zooming or rotating camera. I have a starfield I created using Trapcode Particular. I’m going to apply a Radial Blur to it by going to Effect, Blur & Sharpen, Radial Blur.
The box you first see here when you apply a Radial Blur gives you a preview of the effect.
This blur has two modes: Spin and Zoom. Spin is the default. You can already see how the blur is affecting our starfield. It gives the illusion that our camera is spinning on its Z-axis. As with the other Blur effects, increasing the Amount property will increase the intensity of the blur. If you take a close look, you can see it looks a little rough in some spots. Set Antialiasing to High to fix some of that.
You can also see that we have a Center property. Since both Spin and Zoom base their blurs around a point, we are given the option to choose that point. By default, the Center is set to the exact middle of the composition. But you can move the Center to any point of focus you might need. I’m going to set my Center back to its default, and change the type to Zoom.
I find myself using Zoom far more often than Spin. I love using it to enhance images flying at or around the camera. If I animate the Amount from zero, it starts to look like we’re engaging the hyperdrive on the Millennium Falcon. Unfortunately, increasing the Amount will also increase the noise. To avoid excessive noise, you can lower the Amount, and then duplicate the effect. You will get a similar look with less noise. Here is an example of a Radial Blur set to 75 to compare. You can see that using a duplicated effect with less blur makes for a less noisy image.
I wanted to give you a couple quick examples of appropriate times to use a Radial Blur. In my Chuck Flash tutorial, I created a cylinder that I wanted the camera to fly through. I wanted it to look like the images were really flying by quickly, so I used a Radial Blur set to Zoom. This gave me the look I wanted without having to do much extra work, and it also renders relatively fast compared to using the Force Motion Blur effect, or After Effects’ built in motion blur.
Speaking of render times, here’s a project I just started working on. While it looks fairly simple, this composition is made up of about ten large images. You can see that when I use motion blur, it takes a decent amount of time to render one frame. But if I turn the motion blur off, and instead switch on a Radial Blur, it takes a fraction of the previous time, and there is more blur.