Page 570 - Kitab3DsMax

Part IV: Materials, Cameras, and Lighting Basics

Light coming into a camera is bent through the camera lens and focused on the film, where the image is
captured. The distance between the film and the lens is known as the focal length. This distance is measured
in millimeters, and you can change it by switching to a different lens. On a camera that shoots 35mm film,
a lens with a focal length of 50mm produces a view similar to what your eyes would see. A lens with a focal
length less than 50mm is known as a wide-angle lens because it displays a wider view of the scene. A lens
longer than 50mm is called a telephoto lens because it has the ability to give a closer view of objects for
more detail, as a telescope does.
Field of view is directly related to focal length and is a measurement of how much of the scene is visible. It is
measured in degrees. The shorter the focal length, the wider the field of view.
When you look at a scene, objects appear larger if they are up close than they would be lying at a farther
distance. This effect is referred to as perspective and helps you interpret distances. As mentioned, a 50mm
lens gives a perspective similar to what your eyes give. Images taken with a wide field of view look distorted
because the effect of perspective is increased.

Creating a camera object
To create a camera object, you can use the Create ➪ Cameras menu, or you can open the familiar Create
panel and click the Cameras category button. The two types of cameras that you can create are a Free cam-
era and a Target camera.
Camera objects are visible as icons in the viewports, but they aren’t rendered. The camera icon looks like a
box with a smaller box in front of it, which represents the lens or front end of the camera. Both the Free
and Target camera types include a rectangular cone that shows where the camera is pointing.

Free camera
The Free camera object offers a view of the area that is directly in front of the camera and is the better
choice if the camera will be animated. When a Free camera is initially created, it points at the negative
Z-axis of the active viewport.

Target camera
A Target camera always points at a controllable target point some distance in front of the camera. Target
cameras are easy to aim and are useful for situations where the camera won’t move. To create this type of
camera, click a viewport to position the camera and drag to the location of its target. The target can be
named along with the camera. When a target is created, Max automatically names the target by attaching “.
target” to the end of the camera name. You can change this default name by typing a different name in the
Name field. Both the target and the camera can be selected and transformed independently of each other.

Creating a camera view
You can change any viewport to show a camera’s viewpoint. To do so, right-click the viewport’s title, and
select View and the camera’s name from the pop-up menu. Any movements done to the camera are
reflected immediately in the viewport.
Another way to select a camera for a viewport is to press the C key. This keyboard shortcut makes the active
viewport into a camera view. If several cameras exist in a scene, then the Select Camera dialog box appears,
from which you can select a camera to use. You also can select a camera and choose the Set View to
Selected Camera from the right-click pop-up menu. Figure 19.1 shows two Target cameras pointing at a
car. The two viewports on the right are the views from these cameras.

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