Light on the Camera

by Malefico



In Blender, the camera is our sight. Every scene is rendered from the camera's point of view so it becomes clear that knowing how to handle with the cameras is a very important topic. I will show you here some useful things that are good to know about it. Because of this tutorial's level is basic, many aspects will be repeated once and again, and some others... will not even be mentioned !!!

Just Another Object

Let's start up Blender (ziiiip, it loads really fast, doesn't it ?) and let's set a simple scene to experiment with. Delete the default plane (select it by right clicking on it and press the X key) and add a cube in the same spot (SPACEBAR -> ADD MESH -> CUBE). By now, you probably already know how to change views in the 3D window, but it's never late to repeat it. These are the keys on the numerical pad:

One thing that we have to keep in mind about the camera, is that it is just another Blender object. It can be selected by right clicking on it, moved (by pressing G key and dragging the mouse), rotated (by pressing R key and dragging the mouse) and everything else.Using these keys we are going to place the camera in a way we can see the whole cube. Press NUMPAD 0 to switch to camera view every time you want to check the camera's position. Don't move the other objects, just the camera.

Eventually we'll come to a view like this:

Camera's Properties

Select the camera and press F9 or click on the Edit button to see the camera's properties. You'll see something very similar to this:

These buttons allow us to change every aspect of the camera. We are going to play a little with them. Hold SHIFT and click on the Lens button. This parameter sets the lens amplitude and it has a value of 35 by default. Input a number lower than 35 and press ENTER.

Can you see how the 3D window's view changes ?. With a value of 10 as in the example, we achieve a far and wide view of the scene making visible the cube's surroundings. Using a value of 70 instead, we sort of zoom in the cube. This shows us that is not necessary to move the camera to achieve close-ups or far views of our scene.

Let's Animate !

You will probably be thinking "mmmm... with this I could simulate a close up from far away by progressively changing the Lens value in an animation...", well, that's absolutely right !. Press the I key while in the Properties Edition Panel and a menu like this will pop up:

Click on INSERT KEY -> LENS. Seems like nothing has happened, but we have just inserted a KEY in frame 1 of our animation. For the beginners, here is an explanation: At start, Blender asumes that we are doing an animation and make copies of the current scene in separate frames.

By inserting a a key for Lens in the initial frame (frame 1) we have stored the Lens value for frame 1 in the computer's memory. If we now move a few frames forward, let's say to frame 20, change the Lens value and insert a new key, Blender will calculate automatically the Lens value for the frames in between frame 1 to 20. Clear as mud, isn't it ?.

We will try it for we don't have anything better to do. Let's see how to change to a different frame. Can you see the number in the lower part of the 3D window ?

This means that we are at frame 1. Let's insert a key for Lens as we have seen before (press I key and click on Lens). We are going to move to frame 21 by pressing the UP CURSOR key twice. This key changes the current frame in tens. Can you see the new value ?

Now, we'll repeat the process changing the Lens value to a new value that suit us. Let's insert a key for Lens and move back to frame 1 by pressing LEFT CURSOR key. This key always move us to the initial frame of an animation. Now we'll see the fruit of our exhausting task by placing the mouse over the 3D window and pressing ALT + A. We'll see a nice animation with a zoom in or out to (or from) our scene. Isn't it beautiful ?.

But this is not an animation tutorial, so let's back to our business.

So far away !

Now we'll check out a couple of properties that let us control the reach of our views. These properties are ClipSta and ClipEnd.

When our scene grows bigger and bigger, it could happen that some objects too far way from the camera cannot be visible at all, being substituted by a black hole in our render. ClipEnd controls how far our camera reaches. A high value will let us include in our render all objects no matter how far they are, and in the same hand, a low value will exclude or truncate any object behind the set distance.

Similarly, ClipSta sets the distance where closer objects start being visible to our camera. Any object closer than CLipSta from our camera will be hidden.

In other words, the only objects visible to our camera are those placed at a distance between ClipSta and ClipEnd from the camera.

More cameras, more confusion

It would be nice to have several cameras to switch among them quickly and suddenly during an animation, or to have different views to render of the same object without having to move the camera in between renders.

To add cameras to our scene is a very simple task. Just follow the sequence SPACEBAR -> ADD -> CAMERA.

Well now, if we add 4 or 5 cameras, we could reach the point where things get a little mixed up. To clear things up, we have the Name, Axis, ShowLimits, ShowMist and DrawSize options. Each option's function could be rather obvious, but we'll clear them all with an example.

Let's add three cameras to our scene.

After that, our scene should look like more or less like this.

Select a camera and activate the Name button. We'll see that a little label appears with the camera's name on it. Repeat the operation for each one of the cameras.

Now we'll make visible the cartesian axis by clicking on the Axis button.

This option is very useful when working in a 3D perspective and we are not sure what is up and down.

Another interesting option is ShowLimits which does exactly that. It gives us a quick reference about the reach and direction of the visual field of our camera. Every camera with this option activated will appear with its name in yellow.

In the example we have activated this option for two of our cameras.

By looking at them we can quickly tell which one has the higher or lower ClipEnd or ClipSta value. A straight segment is drawn to show us the distance between both values.

If our scene turned to be REALLY big, another minor problem arises. Our cameras will look so small in comparison that it will be really difficult to select them or check their position. To deal with this we can change the size of the camera's representation on screen by changing the DrawSize parameter.

In the following example we have the same camera with two different settings for DrawSize.

Switching Cameras

If you followed this tutorial step by step, and have been a little impatient, you may have noted that Blender always render from the first camera viewpoint. No matter how many cameras you have added. Time has come to explain how to switch among our thousands of cameras.

In first place, if what we want is ony to check out the view from a particular camera, all we have to do is select THAT camera and press CTRL + NUMPAD 0. Now the 3D view should have changed to the other camera viewpoint. However, F12 will still render with the first camera !.

To make Blender to render from the desired viewpoint, we have to activate the LOCK button in the lower part of the 3D window. With this button activated, Blender will always render using the camera we switched to.

Well, for now that's all about cameras. There are lots of possibilities and tricks or effects we can achieve by wise managing of the camera. We can parent them to a path and make it move following an object (by adding a track). To learn how to acquire these "advanced" skills there are many tutorials in the web, all of them very good. Check out Bart's

Hasta la vista !