滑动变焦（Dolly zoom）是一种破坏正常视知觉来给人以不安感的机内特效。

滑动变焦的做法是，在转动变焦镜头改变视角（视野，FOV）的同时，把摄像机移向或者移离物体，使物体在画面中一直保持相同大小。因此，机位在远离物体的同时，镜头向前推进，或者与此相反。这样画面就会在变焦中就会产生一种连续的透视变形，最直观的特点是背景改变大小而主体不变。

在视觉表现上，或是背景突然变大变丰富有淹没前景之势，或是前景变得巨大无比掌控整个画面布局，具体取决于用哪一种推拉移动方式。人类的视觉感知系统同时用直观大小和透视关系来判断物体的相对大小。因此，看到透视关系改变，而直观大小不变，会给人带来不安感，产生强烈的情感效果。

The dolly zoom is an unsettling in-camera effect that appears to undermine normal visual pe****tion.

The effect is achieved by zooming a zoom lens to adjust the angle of view (often referred to as field of view, or FOV) while the camera dollies (moves) toward or away from the subject in such a way as to keep the subject the same size in the frame throughout. In its classic form, the camera angle is pulled away from a subject while the lens zooms in, or vice versa. Thus, during the zoom, there is a continuous perspective distortion, the most directly noticeable feature being that the background appears to change size relative to the subject.