An in-camera effect is any special effect in a video or movie that is created solely by using techniques in and on the camera and/or its parts. The in-camera effect is defined by the fact that the effect exists on the original camera negative or video recording before it is sent to a lab or modified. So effects that modify the original negative at the lab, such as skip bleach or flashing, are not included. Likewise effects that work with props, such as squibs, fire, and dustball guns are also not included. Some examples of in camera effects include:
References
In-camera effect Wikipedia(Text) CC BY-SA