Cinematographer
From a DoP's perspective, this element is essential for the visual design. It allows me to consistently implement the desired color mood and aesthetic image.
2500W HMI: a 2.5 kW daylight discharge lamp (≈6000 K) with electronic ballast, standard on film sets for high-intensity key and fill lighting.
Overview
"2500W HMI" does not refer to a single product but to a power class of HMI (Hydrargyrum Medium-arc Iodide) lights that operate at a nominal power of 2.5 kW. HMI is a discharge lamp filled with mercury and metal halides; it produces daylight-like light of approximately 6000 K, making it a standard tool for daylight setups on film and TV sets. The 2.5 kW class sits between the compact 1.2/1.8 kW heads and the heavier 4/6 kW units and is frequently used as a Fresnel spotlight.
Well-known examples in this class include ARRI heads like the "Compact 2500," the "True Blue D25," and devices from the M-series; comparable heads are also available from other manufacturers. HMI-2500-W lamps are used as the light source, for instance, from OSRAM in single-ended (G38 socket) or double-ended (SFA21 socket) designs.
Technical Data
The following values refer to typical HMI-2500-W lamps and heads; specific dimensions and weights depend on the respective model.
| Characteristic | Value |
|---|---|
| Power | 2500 W (2.5 kW) |
| Color Temperature | approx. 6000 K (daylight-like) |
| Color Rendering Index (CRI) | approx. 90 |
| Socket (Lamp) | G38 (single-ended) or SFA21 (double-ended) |
| Lamp Lifespan | approx. 500 h |
| Operation | only with electronic ballast (EVG) |
Set Usage
2.5 kW class HMI heads absolutely require a ballast. Electronic ballasts operate at high frequencies and are flicker-free; many EVGs cover both 2.5 kW and 4 kW power levels and allow dimming within a limited range as well as DMX control. For slow-motion recordings, suitable EVGs can be switched to higher frequencies.
Compared to incandescent or LED Fresnels, a 2.5 kW HMI delivers significantly more daylight-balanced light for the same power consumption. Typical uses include illuminating interiors with a daylight character, creating window light from the outside, and supplementing sunlight in exterior scenes.
- Daylight source for interior and exterior shooting without additional conversion filters
- Operates via a separate ballast, connected by a head cable
- Dimmability and color stability are more limited than with LEDs due to the discharge principle
From the crafts
Perspectives
Producer
This professional solution increases production efficiency and reduces post-production demands. It allows for flexible, quick adjustments during the shoot.
Gaffer
As a gaffer, this is an indispensable tool in my daily kit. It allows me professional light control and quick adjustments on set, which saves time and ensures quality.
More in the lexikon
Related terms
Test your knowledge
Quiz
1. Zu welchem Department gehört „2500W HMI"?
2. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?