Join Chris Meyer for an in-depth discussion in this video Focus and convergence, part of After Effects CS5.5: New Creative Techniques.
A lot of people are still feeling their way through this whole stereoscopic production process, and it has caused more than the few headaches if you know what I mean. Part of the problem is, is we may be asking the brain to solve a problem it's never had to solve before. For example, if we're telling the eyes to converge at a point, perhaps the camera I'm looking at right now, that is at a different distance than objects we want the eyes to focus on perhaps text or other objects floating off the screen towards the viewer, well, that's something that brains are not used to doing. They are used to converging on the items that they are trying to focus on.
So it's an important consideration to keep in mind. Also, anything you can do to take attention away from layers the eyes are not supposed to be focusing on, such as using the greatly enhanced Depth of Field blur in 3D camera that is now in After Effects CS5.5, well, that's just going to make your stereoscopic scenes look that much better. So let's take a look at some of these issues and a potential workflow. Right now, my Stereo 3D scene has a problem. Everything is sharp. The far corner of this floor is just a sharp as the front of the floor.
Each of these 3D gears are equally sharp, even though they are at different distances from the viewer. The text are sharp. The back view is sharp. This can cause some confusion for the viewer's brain as to what to focus on and that sort of confusion is what can induce headaches in viewers of stereoscopic material. Well, there is one tool to help cure this, is the improved depth of field parameters for cameras in After Effects CS5.5. You might remember from the last movie that I locked this Composition viewer so I can keep looking at my stereo output while I played around in earlier comps.
I'm going to do the same thing now. I'm going to keep this locked so I'm always looking at this view with my 3D glasses on. If I'm going to go back to my original composition, so I can work with this camera's Depth of Field parameters. I'll type AA to bring up all the Depth of Field params. I'm going to enable Depth of Field. Initially, I don't see much difference, because the Aperture defaults to a pretty small size. So I need to increase the Aperture to narrow down my focal plane. Now the good news is this parameter has already been linked by expressions, thanks to the 3D Rig tool, to the cameras in the left and right views.
The bad news is though I have to release the mouse before those comps update. So I'm trying to increase it a little bit, release, and now I see improved depth of field. Increase a little bit more, release. That's the new result. Let's just go ahead and bring it to a nice number like 200 for now, with an exaggerated narrow depth of field to really see what I'm doing. Right now, no one is in focus. Let's say that I want that text Virtual Industry to always be my hero. I'll select that layer and hold Command on Mac or Ctrl on Windows and also click on Camera 1, so both the camera and the target layer are selected.
Then go up to Layer > Camera > Set Focus Distance to Layer. That will automatically set the Focus Distance parameter to make sure that text is nice and sharp, and you'll see now that the forward gear is blurred, the forward edge of the floor is blurred, the back edge of the floor is blurred. This makes it easier to tell the user's brain what to focus on, what to pay attention to. I can go ahead and check out later in the comp and now those forward gears are particularly out of focus the text is more or less in focus behind it.
You see I've set that focus distance at that particular camera view. If I want to lock them together, I'll make sure the Virtual Industry, my text, and the Camera are both still selected, then go to Layer > Camera > Link Focus Distance to Layer, and this will dynamically update the Focus Distance parameter to always keep that text in focus, no matter where the camera is during the course of this animation. So using Depth of Field is already a big improvement.
I'll set this to a better iris simulation like Hexagon and get a cleaner render out of these objects. However, by doing this we are committing another sin. We've locked our cameras Focus Distance to always focus on the text Virtual Industry. However, back in our stereoscopic comp, we've locked our Convergence point to the Camera Point of Interest, and the Point of Interest is not necessarily where that text layer is. Ideally, we want our focal plane and the point we converge on to be the same.
That way the eyes are converging and focusing at the same distance away from the viewer. So how would we go about doing that? Well, there are a couple of approaches. I'm going to turn off the Lock icon. So I'm going back to switch in between compositions normally. I'll go back to my final comp and take a look at what this camera is doing. I'll switch back to 2 Views- Horizontal and I'm going to look at this camera's point of interest. It so happens it's already been set up to animate along this plane, which happens to be the same plane that this gear is located on, not the plane that the Virtual Industry text is located on.
One option would be to reanimate the camera so that the point of interest was where the text was. Another option would be to try to line up the zoom plane to the layer I want to keep in focus, because the zoom plane is another option I have back in my Convergence parameters. But let's say that changing the camera's animation is not an option at this point of the production process. Well, that's okay. We have another parameter to help bail us out. Remember the Stereo 3D Controls had a parameter called Convergence Z Offset.
Is there an offset you want to enter from the point of interest, the camera's position, or the zoom distance where you really want the left and right cameras to converge? Well, that happens to be exactly what we need right now. I'm going to go back to my main comp, look at my text layer, type P to reveal its Position, and I see that its z distance is 300. Then I'm going to look at where the camera's point of interest is by selecting it, typing Shift+A to reveal the Point of Interest in addition to the parameters, and I see that it is at 0 as opposed to 300.
That would make a good starting point for a Z offset value. Now of course as this camera moves around the scene, there are going to be some differences between exactly where the focal plane falls and where the Z offset is. But this is going to get us really close for our shot. So switch back to our final comp and enter a Convergence Z Offset of 300 pixels. 300 further back from the point of interest back to where the Virtual Industry layer is.
If you're not wearing any special glasses, this may look like a bit of a mess right now. But if you are wearing red/blue glasses right now, you will see that the whole scene has looked forward to the point where Virtual Industry is now on basically the plane of the screen. The gears will move further forward and the video plane has moved back a little bit from the text. I'm now converging and focusing on the same point. We'll just jump around to a couple of different points in time here. Now we're moving the scene in a way that Virtual Industry is staying on the same plane that we're focusing and converging on, and at the end of day this will be an easier scene to view.
Now to be honest, this is not something you want to be trying to change after the fact. Now that you have this bit of knowledge, use it when you set up your camera animation initially, so that you place either the zoom plane or the focal plane on the object you want the viewer to be focusing on and you'll end up with a better stereoscopic experience.
After Effects CS5.5 New Creative Techniques was created and produced by Trish and Chris Meyer. We are honored to host their material in the lynda.com Online Training Library®.
- Adjusting the parameters in Warp Stabilizer
- Creating orbiting camera rigs
- Using the Camera Lens Blur effect
- Understanding focus and convergence
- Processing audio dynamically