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Maxwell Render 2.5 User Manual

Chapter 12. Maxwell Studio | 113

12.04.04 Depth of Field (DOF)

Related to the focus concept, Depth of Field is one of the most important concepts in

photography.

F.01 The camera is pointing to the interest area

The focal distance should be the distance from the camera to the object in order to get

a perfectly focused image. The near and far planes dene the DOF area. Inside the DOF

area, all objects are in focus.

The most important camera parameters to remember regarding the DOF are the f-Stop

and Focal Length.

• The Focal Length of a lens refers to the distance between the lens and its focal

point. The focal point is where the light will be focused, usually where the lm is.

The focal length of a lens determines the eld of view (FOV), or how much you

see of your scene, and also the DOF. A small focal length lens (15-24mm) is said

to be a wide-angle lens because it captures a lot of the scene (it has a wide FOV),

and its DOF is wide too: almost all the objects in the scene will be in focus. A

large focal length lens (80-200mm) is said to be a telephoto lens. It acts like a

binocular, “zooming” in to a particular area of your scene. It has a small FOV and

the DOF will be very narrow too: only a small portion of your scene will be in focus.

Which focal length to use is completely up to you and depends on your needs. An

architectural scene may need a wide-angle setting to capture more of the scene

and make sure everything is in focus. A larger focal length can be suited for product

photography or characters because a wide-angle lens tends to distort the objects that

are close to the camera and you may want to avoid this in certain cases.

• The f-Stop indicates how opened or closed the diaphragm is. The diaphragm is a thin

opaque structure with an opening (aperture) at its center. The diaphragm stops the

passage of all light except for the light passing through the aperture. The diaphragm is

placed in the light path of a lens, and the size of the aperture regulates the amount of

light that passes through the lens. The smaller the f-Stop (1.8, 2.2, 2.8) the narrower

the DOF, so only a small area of the image will be in focus.

The Maxwell camera has a visual focus indicator that provides information about the focus

conditions of the target. When the camera moves, the focus indicator changes according

to the distance from the camera to the objects. The focus indicator is composed of two

circles and a rectangular indicator in the center of the camera. When the target object

(the central point of the circles) is exactly in focus, the rectangular indicator turns yellow,

otherwise it remains black.

A black rectangular indicator does not necessarily mean that the render will be out of

focus, it also depends on the total DOF. To measure if the camera target is inside or

outside the DOF distance, the circles use blue or red colors. When the circle turns red, it

means that the specic target area is beyond the far plane. Conversely, when the circle is

blue, the target area is located in front of the near plane.

Areas in red and blue are in “out of focus” zones. Transparent areas are in focus. The

yellow mark is the exact focal point.

Shortcut: Press the “I” key to disable or enable this information in the display.

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Arrow Group Industries LM86 Manual do Utilizador Página 113