Special effects in cinema are divided into two categories:

1) Field special effects
Special effects in the film industry are images that are difficult to make when making a film. These scenes are real and real, and all of them are performed by stuntmen, artists, cinematographers and a number of explosives and modeling specialists, and are recorded with the cameras themselves, and some of them are filmed after the recording.


Special effects are divided into two categories: optical effects and mechanical effects.


Optical effects
(Also called photo effects) are techniques in which images or film frames are created in the form of a photograph, which is through “in-camera” using multiple exposures, combining images or the process of shaftan, or through post-processes. Produced by and using an optical printer.


Mechanical effects
(Also called practical or physical effects) are techniques that are actually recorded during the original filming. This includes mechanical objects, staging, scale models, fireworks, and atmospheric effects (creating effects of wind, rain, fog, snow, and physical clouds). Creating a car with automatic movement or blowing up a building are examples of mechanical effects.


Before computers could produce such images, filmmakers also made many cinematic special effects. They used plaster models, cardboard samples, dolls, and scaled-down models to create these effects. Of course, the concept of Special Effects means special field effects with Visual Effects meaning visual effects should not be confused. Special effects are those that are actually performed by stuntmen in the field.


2) Special visual effects
Today, special effects are used if it is impossible or costly to create a live effect in front of the camera. Special effects include composites, rotoscopes, animations, tracking, etc., most of which are expensive to make and add a significant amount to the cost of producing Hollywood movies.