Dolly zoom

src: i.ytimg.com

The dolly zoom is an in-camera effect that seems to ruin the normal visual perception.

The effect is achieved by zooming the zoom lens to adjust the viewing angle (often referred to as the field of view, or FOV) while the doll camera moves toward or away from the subject in such a way as to keep the subject of the same size in the entire frame. In its classical form, the camera angle is pulled away from the subject as the lens zooms, or vice versa. So, as long as the zoom, there is a continuous perspective distortion, the most visible feature is the background seems to resize relative to the subject.

The visual view for viewers is that the background suddenly grows in size and detail and master the foreground, or the foreground becomes very large and dominates the previous setting, depending on the way in which zoom dolly is executed. Because the human visual system uses size and perspective guidance to assess the relative size of an object, seeing a change of perspective without size change is a very disturbing effect, often with strong emotional impact.

The effect was first conceived by Irmin Roberts, Paramount's second unit cameraman, in the film Alfred Hitchcock Vertigo .

In addition to Vertigo shots have been used in many movies, including Goodfellas , The Road to Hate , Jaws , Double , Dr. Island Moreau , and Josie and Pussycats .

Video Dolly zoom

Alternate name

Zoom counter dolly is also known as:

• Focus zoom error
• "zido"
• A "zolly"
• Hunter Smith Shot
• "Hitchcock shot" or " Hunter shot "
• "Hitchcock Zoom" or " Vertigo " effect
• Vertigo zoom
• A "Jaws shot"
• Reverse Trackback Shoots
• Threefold Zoom
• Return Trip Zoom
• "Smash Zoom" or "Smash Shot"
• Telescoping
• Trombone shot
• Push/drag
• Drag Length
• Drag Backwards
• Trombone effect
• A stretch shot
• More technical like zoom ahead/trackback or zoom in/out dolly
• Trans-trav (in Romanian and Russian), from long trans-focal operation and traveling movement
• Contra-zoom

Maps Dolly zoom

Purpose of effect

The dolly zoom is commonly used by the filmmaker to represent the sensation of vertigo, "feelings of self" or unreal feelings, or to show that the character is experiencing a realization that causes him to reevaluate everything. he previously believed. After Hitchcock popularized its effect, he used it again for climax revelation at Marnie .

src: i2.wp.com

Optics

Untuk sebagian besar tujuan, dapat diasumsikan bahwa ruang gambar dan ruang objek berada dalam medium yang sama. Jadi, untuk objek dalam fokus, jarak antara lensa dan bidang gambar ${\ displaystyle s _ {\ text {i}}}  ÂÂ$ , jarak antara lensa dan objek ${\ displaystyle s _ {\ text {o}}}  ÂÂ$ , dan panjang fokus ${\ displaystyle f}  ÂÂ$ terkait oleh

${\ displaystyle {1 \ over s_ {i}} {1 \ over s_ {o}} = {1 \ over f}.}  ÂÂ$

Kemudian pembesaran transversal adalah

${\ displaystyle M = {s _ {\ text {i}} \ over s _ {\ text {o}}} = {f \ over (s _ {\ text {o}} -f)}.} Â Â$

One can see that if magnification remains constant, longer focal lengths result in smaller axial enlargements, and smaller focal lengths in larger axial enlargements. That is, when using a longer focal length when moving the camera/lens away from the object to maintain the same magnification M , the object looks more shallow, and the axial distance between the objects appears shorter. The reverse - an increase in axial magnification - occurs with a shorter focal length when moving the camera/lens to the object.

Calculate the distance

To achieve the effect, the camera needs to be positioned at a certain distance from the object that should remain stationary during zoom dolly. The distance depends on how wide the scene will be filmed and in the field of view (FOV) of the camera lens. Before calculating the required distance in different fields of view, the constant width of the scene should be calculated:

                                                     1                     2                 <      ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ,                                     FOV     ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ,        ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ, <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<                                      .               {\ displaystyle {\ text {distance}} = {\ frac {\ text {width}} {2 \ tan \ left ({\ frac {1} {2}} {\ text {FOV}} \ right)}}.}  Â

For example, FOV 90 Â ° and a distance of 2 meters yields a constant width of 4 meters, allowing a 4 meter wide object to remain within the frame during effect.

src: i.ytimg.com

References

src: www.slate.com

External links

• The Vertigo Effect article on Tropes TV

Source of the article : Wikipedia