In-camera or practical effect — explosions, blood, fire, mechanical rigs. Physically present on set, not post-produced.
When the camera is rolling and something actually explodes, burns, or bleeds in front of the lens, then you're working with special effects. This is the artisanal foundation — not digital, not post-produced, but physically present on set. A special effects supervisor ignites the charge, an effects technician makes the blood spray, a pyrotechnician sets the flames. The DoP has to work with real light waves reflecting off real objects.
The crucial difference from VFX lies in real-time control. Unlike computer-generated effects, special effects cannot be re-rendered an arbitrary number of times or adjusted in post-production. You build them, test them, and then they have to work on the take — or you shoot again. This creates a different density on set: higher tension, more precise planning, real consequences. The lighting mood, the shadows, the particle movement — everything is captured in reality and can only be manipulated within limits later.
Typical applications: explosions and pyrotechnic sequences (fall control, timing to the millisecond), practical blood effects for violence or horror scenes (latex constructions, pump-controlled systems), fire and smoke (smoldering fires, controlled campfires, roof fires), mechanical destruction (falling objects, facade collapses with stunt rigging), driving stunts (rollovers, collisions with braking systems). On larger productions, there's a dedicated special effects department — one or more supervisors coordinate safety, materials, and technical feasibility.
In modern hybrid productions, special effects are often combined with VFX. You shoot a real, but controlled explosion — not maximally destructive, but camera-optimized — and VFX then enhances or supplements it in the edit. This gives the scene weight and credibility that pure CGI often cannot provide. From a camera perspective, this means: pay attention to shadows, to color shifts from smoke or fire, to vibrations and motion blur. Special effects are uncontrollable in real-time — the DoP has to rely on their eye and capture multiple options.