Panasonic AVCCAM AG-3DA1 Скачать руководство пользователя страница 3 | Manualshive

Страница: 3 / 11

Panasonic AVCCAM AG-3DA1 Скачать руководство пользователя страница 3

3

Convergence, Parallax, and Depth

When the parallax value of the pair of images of an object is negative, the left-eye image
of the object is seen on the screen at a position that lies to the right of its right-eye image.
When a viewer converges the image pair, the 3D object seems to be located in front of the
screen plane. When the parallax value of the image pair is positive, the left-eye image of
the  object  is  seen  on  the  screen  at  a  position  that  lies  to  the  left  of  its  right-eye  image.
When  a  viewer  converges  the  image  pair,  the  3D  object  seems  to  be  located  behind  the
screen plane. When the parallax value is zero, the two images of the object overlap at the
screen  plane.  In  this  circumstance  the  object  seems  to  the  viewer  to  be  located  on  the
screen plane. When a viewer’s eyes are focused on the screen and converged on an object
that appears to be in front of the screen (i.e. an object with negative parallax), the viewer’s
left and right eyes cross. And when a viewer’s eyes are focused on the plane of the screen
and converged on an object that appears to be on or beyond the screen (i.e. an object with
zero or positive parallax), the viewer’s eyes remain uncrossed. Because crossing the eyes
can  cause  physical  discomfort,  filmmakers  are  often  cautious  about  using  excessive
negative  parallax,  choosing  instead  to  limit  the  degree  to  which  objects  are  allowed  to
intrude into the viewer’s space

1

.

1.

eyes focused on screen, left image

2.

eyes focused on screen, left image

    to right of right image (negative                     to left of right image (positive
    parallax). The object seems to be                 parallax). The object seems to be
    located in the viewer’s space                        located in the screen space

(in front of the screen), or in (beyond the screen), or in
negative z-space. positive z-space.

Fig.3 – Convergence, Parallax, and Depth

______________________________________________________________

1.

This caveat applies in particular to smaller-screen venues. In giant screen venues such as

traditional IMAX theaters—with screens up to five times the size of those in digital cinemas—
negative parallax is considered to be easier to experience, affording viewers the sense that they
are not simply

watching

a film but that they are

immersed

in it. This immersive factor, which can be

attractive to Hollywood films, is an argument in favor of the development of digital projectors that
are capable of displaying bright images on giant screens.

«
1
2
3
4
5
...
»

Содержание AVCCAM AG-3DA1

Страница 1: ...s Fig 1 Real World 3D Simulated 3D The experience of viewing a 3D film is significantly different from the way a viewer sees 3D in the real world The most obvious differences between real world 3D and the simulated 3D that is viewed on a screen are a consequence of the fixed depth of field and the fixed point of view of the lenses that capture the images As a result of these constraints viewers wa...

Страница 2: ...y strongly converging their lenses 3D filmmakers can cause the spatial geometry of a scene to seem to warp as if the space were bending toward or away from the viewer Effects such as these though unwanted in productions that aim to portray the world as it is can be useful tools for a filmmaker producing a surrealistic or fantasy film With its unique capabilities 3D is not merely a tool for adding ...

Страница 3: ... e an object with zero or positive parallax the viewer s eyes remain uncrossed Because crossing the eyes can cause physical discomfort filmmakers are often cautious about using excessive negative parallax choosing instead to limit the degree to which objects are allowed to intrude into the viewer s space1 1 eyes focused on screen left image 2 eyes focused on screen left image to right of right ima...

Страница 4: ...on the screen plane and C 5 refers to a shot with lenses moderately converged pulling the viewer into the screen space In terms of I O the use of wider than normal and narrower than normal camera configurations as noted above can introduce unwanted distortions However the informed use of exaggerated interoculars can help filmmakers enhance the impact of their stories A wider than normal interocula...

Страница 5: ...e involves toeing in the lenses of the cameras so that the right and left images of a particular target overlap The target for setting convergence may be an object in the scene or a slate held in front of on the plane of or beyond the plane of a subject Fig 5 Image Capture The convergence point that is chosen by the filmmaker establishes the position of the zero parallax plane in the image This pl...

Страница 6: ...cular and the width of the target screen Post Processing If decisions regarding convergence are deferred until post the images from the left and right eyes may be converged by the process called depth grading or horizontal image translation HIT This technique see Fig 7 involves horizontally displacing the right and left images to produce negative zero or positive parallax values on the screen plan...

Страница 7: ...eme limit of positive parallax beyond the screen should be a comparable distance A larger negative parallax value may force viewers to cross their eyes to an uncomfortable degree and a larger positive parallax value may force viewers to diverge their eyes to an uncomfortable degree the so called wall eye effect Because the depth of the comfort zone is dependent upon screen size 3D films designed f...

Страница 8: ...ene that they want the audience to see For example a street that winds away into the distance can help to set the actors apart from the background or the use of smoke dim lighting or cooler hues can help to direct the audience s attention to foreground subjects that are more clearly defined more brightly lighted or shaded in warmer tones In addition to take advantage of the unique capabilities of ...

Страница 9: ... or post that affects one eye but not the other can induce retinal rivalry a conflict between the components of the stereo pair that disrupts the web of illusions that produce effective 3D Filming Live Events When shooting live events such as stage performances and spectator sports 3D filmmakers confront several limitations that can compromise their ability to capture effective 3D Foremost among t...

Страница 10: ...rization effect that results from an overly wide I O Along with the above live event filmmakers like all other 3D filmmakers are generally advised to reject long focal length lenses in favor of those with a wide depth of field Pacing the Cut The caveats that apply to 3D production also apply to the art of composing 3D films in post In addition to carefully matching convergence and interocular dist...

Страница 11: ... parallax plane or screen plane divergence the unnatural outward rotation of the human eyes to view images with an interocular that is larger than that of the average human eye 2 5 Results in wall eye interocular horizontal displacement of the lenses of the cameras hyperstereo the effect of an interocular that is larger than that of the average human eye 2 5 miniaturization an artifact that result...

Отзывы:

Нет отзывов