CAP 202 - Computer Animation II

Lesson 18 - Cameras

Objectives:

This lesson describes the camera in 3DS Max and their use. Objectives important to this lesson:

  1. Target and Free cameras
  2. Framing camera shots
  3. Lens sizes and Aspect ratios
  4. Camera angles
  5. Line of action
  6. Animating cameras with paths
Concepts:

The text explains that you will use two types of cameras in 3DS Max:

  • target cameras are linked to a location in the scene to keep the camera looking at that location even when the camera moves
  • free cameras require manual settings; they do not automatically look at any location, nor do they move with an object. They are pointed at whatever they point at when they are created until they or the objects they point at are moved.

    As an aside, a camera can also be made to face an object in the scene, regardless of movement, with the LookAt Constraint, found on the Animation, Constraints menu.

Basic camera shots are listed, along with some guidelines to categorize the shots you make. The guidelines are based on having a human being as the focus of the shot. For shots that do not include people, use whatever the main object is as the measuring stick:

  • long shot - includes the entire subject, head to foot. Fred Astaire had a clause in his contract with MGM that said he was to be photographed this way every time he danced on screen.
  • medium shot - shows a standing subject from the head to about the knees
  • close-up - shows mostly the head of a subject, may include shoulders, but ends above the waist
  • extreme close-up - shows a portion of a face, or a portion of an object
  • extreme long shot - not listed in the text, since people are often not visible in this shot that shows a cityscape, or landscape to establish the location of the next shot (also called an establishing shot for the obvious reason)
Exercise Notes and Questions

Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.

Exercise 1: Open the the indicated file, and create a target camera as instructed.
In step 5, the Truck Camera button is the Pan button. underwater scene as instructed. Ignore the yellow structures on the scene for now.
In steps 6 through 8, you will use the dolly and truck tools to adjust the shot. In some film courses, truck, track, and dolly mean the same thing: moving the camera. In 3DS Max, to truck the camera is to move it up, down, left, or right. To dolly the camera is to move it toward or away from the subject. To zoom the camera is to adjust the lens to magnify or reduce the image.

Exercise 2: Continue with your open file and create a free camera as instructed.
As before, truck and dolly the camera to get the desired shot.
Question 1: What are you told about the orientation of a free camera when it is created?

Camera lenses in the real world have characteristics that are related to their focal length. 3DS Max uses equivalent measurement to simulate the effects of longer and shorter lenses in its cameras. A related concept is Field of View (FOV). This is measure of how wide a portion of the scene a camera can see. The longer a lens is, the narrower the FOV. The shorter a lens is, the wider the FOV. In the real world, we need to change the lens on a camera to change the focal length. In 3DS Max, we can change to one of several Stock Lenses with a click on the Modify panel.

The text gives us a rule of thumb for categorizing lenses:

  • focal length 30mm or less - wide angle lens; makes the background look farther away from the foreground, includes more foreground than a regular lens
  • focal length between 30mm and 200mm - standard lens, the extremes will have some characteristics of the kind of lens they are closer to
  • focal length 200mm or more - telephoto lens; makes the background look closer to the foreground

Exercise 3: This exercise shows you what happens when we change to a different focal length for a camera.
Open the indicated file. Note that it starts with a camera that has a wide angle lens.
In step 3, you are reminded of a mouse technique to copy the camera. The copy is still a wide angle lens in step 5.
Question 2: What is the effect of placing a wide angle lens far from the subject being photographed, as seen in step 5?

Step 8
sets the focal length of the new camera to a real telephoto length (300mm). Step 9 moves the camera farther away from the subject. It also puts the camera behind a wall in the scene.

Clip ManuallyThis leads to some 3DS Max magic. In step 10, to use the camera at its current distance from the subject, but to get it to ignore the wall between the camera and the subject, turn on Clip Manually to control what the camera sees. The Near Clip value tells the camera where to start seeing, and the Far Clip value tells the camera where to stop seeing.

Step 11
tells you to bring the mountains into the camera's picture by changing the Far Clip value to 1000'. This also gives us a portion of the sky, and makes the horizon look a lot closer than in the wide angle view of the original camera.
Question 3: At what value for the Far Clip parameter did the mountains start to appear?

The text moves on to briefly discuss aspect ratios. Here are some links to interesting information about aspect ratios:

Exercise 4: The text has you change the aspect ratio for the scene, using the dropdown box on the Output Size rollout. You could change it manually, or by clicking one of the available preset buttons. Note that when you make a change with the dropdown list the aspect ratio of your choice appears in the lower left corner of the rollout.
Question 4: What aspect ratio appears for the choice in step 3?
Question 5: What aspect ratio appears for the choice in step 5?

The text moves on to camera angles. This topic is also discussed under the first link on this page. The angle of a shot may be dictated by the logical position of the viewer, or it may be meant to set a mood.

Exercise 5: In this exercise you create a camera and move it as directed in the scene. For the last three steps, you may need to change between the Select, Select and Move, and Select and Rotate controls for the scene.
Question 6: Which tool lets you change the angle of the camera?

The text moves on to discuss perspective, specifically one-point, two-point, and three-point perspective. The link in the last line will take you to a pleasant site that discusses all three. In general:

  • one-point perspective gives the illusion of depth
  • two-point perspective adds the illusion of three dimensions to objects
  • three-point perspective adds the illusion of looking up at something very tall, or down at something very deep

The problem this section of the lesson is leading us to is that sometimes perspective can be incorrect in a scene, but we can force it to work as shown in exercise 6.

Exercise 6: Open the indicated file, and look at the perspective problem with the telephone poles in the scene.
In step 2, you may find it difficult to select the camera in the indicated viewport.
Question 7: If you cannot see the camera in the scene, what else might you click to select the camera?
You need to add the Apply Camera Correction Modifier to the camera from its quad menu. It is not available from the Modifier list. When you add this modifier, it automatically makes a perspective correction to the scene.
Question 8: What are you told to do that puts the perspective out of synch again?

The text discusses line of action next. In the context of this text, this phrase can mean a line, or plane, or space in a scene on which the action to be captured will take place.The text recommends that we establish a line of action for a scene, and place our cameras at strategic locations around it. It also states that we should not cross the line of action, but this seems like a rule made to be violated, especially in scenes where we circle the subjects, such as the dance sequence in Beauty and the Beast. This sequence is much better for the fact that the camera moves around the subjects, crossing their line of action dramatically.

Exercise 7: Open the indicated file, and look at the two characters in a police interrogation room. You will set up three cameras to take shots of the pair of characters, and each character individually.
In step 11, you will set the first copy camera to be the camera for one of the viewports. When you do this, the scene may go dark or gray. Press F3 a few times and it should resemble the illustration in the text.
Question 9: Describe the geometry of the three cameras you place in the scene, in terms of this exercise.
At the end of the exercise, save the file with a new name.

Target Camera Triangle

Exercise 8: The key to this exercise is to learn to convert a free camera to a target camera. This is not done the same way it is done when you create a camera.
Question 10: What must you do to change a free camera into a target camera?

Note that when they are selected, free cameras are shown with a triangle marking their Field of View. The camera is at the apex of the triangle. Target cameras have a triangular Field of View as well, but their triangles have a square target marker in the middle of the base. In the image on the right, the cameras are light blue (one behind each character figure), the triangle of the selected camera is blue-white, and the target marker of the selected camera is a white square. The mouse pointer in the image is pointing at the target marker. In the image, the target marker has been selected, as it must be to move it.

Continue working with your version of the file above. You will find it necessary to move the target markers and the cameras in all three dimensions to obtain the desired result.


The text moves on to the last subject for the lesson: moving cameras. As was noted above, there are advantages to the cameras used in 3DS Max (and other virtual environments). We can move them as we like, without regard to the physical limitations a camera crew faces on a movie set. Some basic terms are reviewed:

  • panning - changing where a camera is pointed by rotating it
  • trucking/tracking - changing where a camera is pointed by changing the camera's location; typically this term is used when a camera moves to follow a subject
  • push-pull - moving the camera toward a subject, then away from it
  • crane effect - in movies, a crane shot places a camera on a crane that moves it above the scene. In 3DS Max, we will create a path for the camera to follow. The path must go where the crane would have put the camera.
  • Follow this link to a Yale page about movie terms for more terms and a few example videos

Display panel buttonExercise 9: This exercise adds another shot to our interrogation scene. Open the indicated file. It has a path in it that we will use for a crane shot.

In step 2, choose the Display panel, the fifth 3DS Max panel button. (I don't think we have used it yet in this class.) The loaded scene is already hiding shapes. Tell it to stop doing that, so you can work with the path shape. (You would hide it again before you rendered the scene.)

In step 5, you select the camera target from the quad menu. You are told to move the target in step 6. You need to click the Select and Move tool before you can move the target marker.

In step 8, you learn why it was not important where you made the camera. Use the process described to connect the camera to the path in the scene.
Question 11: What is the process to connect the camera to the path?