| rdfs:comment
| - The Depth Of Field effect simulates a camera that’s focusing at one depth (focal plane) in a 3D scene, blurring objects at other depths. This effect uses the depth information from the auxiliary channel of an imported file representing a 3D scene. To use the depth information that After Effects calculates for a camera layer, see Create a camera layer and change camera settings. This effect works with 8-bpc, 16-bpc, and 32-bpc color.
- Depth of field (DOF) is the distance in front of and behind the subject which appears to be in focus. For any given lens setting, there is only one distance at which a subject is precisely in focus, but focus falls off gradually on either side of that distance, so there is a region in which the blurring is tolerable. This region is greater behind the point of focus than it is in front, as the angle of the light rays change more rapidly; they approach being parallel with increasing distance.
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| abstract
| - The Depth Of Field effect simulates a camera that’s focusing at one depth (focal plane) in a 3D scene, blurring objects at other depths. This effect uses the depth information from the auxiliary channel of an imported file representing a 3D scene. To use the depth information that After Effects calculates for a camera layer, see Create a camera layer and change camera settings. This effect works with 8-bpc, 16-bpc, and 32-bpc color.
- Depth of field (DOF) is the distance in front of and behind the subject which appears to be in focus. For any given lens setting, there is only one distance at which a subject is precisely in focus, but focus falls off gradually on either side of that distance, so there is a region in which the blurring is tolerable. This region is greater behind the point of focus than it is in front, as the angle of the light rays change more rapidly; they approach being parallel with increasing distance. Several factors determine whether the objective error in focus becomes noticeable. Subject matter, movement, the distance of the subject from the camera, and the way in which the image is displayed all have an influence. However, the most important factor is the actual degree of error in relation to the area of film exposed. Light from a point source at the correct distance will produce the image of a point on the film. A point farther away or nearer will produce the image of a disk whose border is known as "circle of confusion." The diameter of these circles increases with distance from the point of focus and so can be used as the measure of error or blurring of the image. For a 35 mm motion picture, the image area on the camera negative is roughly 0.87 by 0.63 in (22 by 16 mm). The limit of tolerable error is usually set at 0.002 in (0.05 mm) diameter. For 16 mm film, where the image area is smaller, the tolerance is stricter, .001 in (0.025 mm). Standard depth of field tables are constructed on this basis, although generally 35 mm productions set it at 0.001 in (0.025 mm). Note that the acceptable circle of confusion values for these formats are different because of the relative amount of magnification each format will need in order to be projected on a full-sized movie screen. (A table for 35 mm still photography would be somewhat different since more of the film is used for each image and the amount of enlargement is usually much less.) Another factor to be considered is that the film format's size will affect the relative depth of field. The larger the area of the film is, the longer a lens will need to be to capture the same framing as a smaller film format. In motion pictures, for example, a frame with a 12 degree horizontal field of view will require a 50 mm lens on 16 mm film, a 100 mm lens on 35 mm film, and a 250 mm lens on 65 mm film. Conversely, using the same focal length lens with each of these formats will yield a progressively wider image as the film format gets larger: a 50 mm lens has a horizontal field of view of 12 degrees on 16 mm film, 23.6 degrees on 35 mm film, and 55.6 degrees on 65 mm film. What this all means is that as the larger formats require longer lenses than the smaller ones, they will accordingly have a smaller depth of field. Therefore, compensations in exposure, framing, or subject distance need to be made in order to make one format look like it was filmed like another.
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![[RDF Data]](/fct/images/sw-rdf-blue.png)