ARRI M18

Last Updated 15 hours ago

Overview

The M18’s combination of output, manageable head size and compatible 1,200/1,800W operation makes it a familiar location tool. A working package still needs the correct ballast, lamp, header cable and supply; the lamphead alone is not a plug-in mains fixture.

Key specifications

Specification	Details
Fixture type	Open-face metal-halide daylight lamphead
Optical system	Faceted MAX reflector; no spreader lens required for normal focus
Approved power classes	1,800W or approved 1,200W
Lamp base	G38
Nominal CCT	6,000K, ARRI listing
Focus range	20–60° on product page; data sheet tests 15–58°
Dimming	50–100% through a compatible ARRI ballast
Head weight	Approximately 11.5kg
Support interface	28mm / 1⅛in junior spigot
Scrim / door size	330mm scrim / 344mm barndoor
UV-protection glass diameter	276mm
Weather rating	IP23
Maximum ambient temperature	45°C
Ballast	Separate compatible ARRI electronic ballast required

Strengths and limitations

Strengths

• A hard daylight source supports throw, bounce and large diffusion.
• Matched ballast options support production control.

Limitations

• Lamp, reflector or lens and ballast must be specified as a complete system.
• High-speed performance depends on the actual lamp, ballast mode and camera test.

Practical uses

The MAX reflector allows focus adjustment while retaining a hard-source character. Focus changes coverage and central illuminance. A narrow spot can be useful at distance, while flood may fill a bounce or diffusion frame more evenly. Check the actual distribution instead of selecting focus only for its centre reading.

Barndoors reduce unwanted spill, scrims reduce intensity without the same colour change as electrical dimming, and supported softboxes provide another distribution. All accessories add weight or heat considerations. Use the correct diameter and approved accessory arrangement.

The M18 remains a useful choice for a controlled daylight push where its hard-source optics and existing rental ecosystem suit the job. Its lower lamp class can make it easier to deploy than larger HMIs, but the actual circuit and ballast still decide whether a location supply is adequate.

Compare it with tunable-white LEDs using the same working distance, useful coverage and modifier losses. An LED offers electronic colour tuning; the HMI offers its own beam and system characteristics. The HMI explainer covers the technology behind the fixture.

Setup	Working approach
Window or exterior push	Choose beam coverage and throw before calculating the required circuit and rig.
Large diffusion	Meter the useful lit area after diffusion and allow for transmission loss.

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Output and colour

The values below come from the ARRI data sheet, with the 1,800W lamp configuration. Lamp condition, focus and the complete optical setup affect practical output.

Distance	Spot 15°	Medium 40°	Flood 58°
7m	22,950 lux	4,325 lux	2,245 lux
10m	11,250 lux	2,120 lux	1,100 lux
15m	5,000 lux	940 lux	490 lux

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Power and batteries

ARRI lists 140V for the 1,800W lamp and 100V for the 1,200W lamp at the head. Those are not a statement that the lamphead accepts household mains directly. The ballast supplies and controls the discharge lamp.

Plan the electrical supply from the actual ballast’s input label, operating mode, cable and other connected loads. Lamp wattage does not include every part of the mains-side system. Match the selected lamp power to an approved ballast and header cable.

ARRI lists the EB MAX 1.8 and appropriate 1,200/1,800W ballast systems in its documentation. A 1,200W arrangement and an 1,800W arrangement have different output and supply demands; specify which one is required on the lighting list.

The ballast also affects startup, dimming, high-speed capability, sound and control options. Read its manual along with the head’s manual. Any DMX or remote-control features belong to the chosen system; they should not be attributed to the bare lamphead without that qualification.

Control, cooling and camera operation

The nominal 6,000K listing is a reference for the discharge source, not an electronic CCT setting. Lamp age, power mode, diffusion and correction media can affect the match. Meter or test through the production camera when matching other HMIs, LEDs or real daylight.

Dimming is through the ballast within the approved range, rather than through an ordinary external tungsten dimmer. A high-speed-capable ballast is useful, but flicker performance still needs a test at the intended frame rate, shutter, lamp power and focus. “HMI” alone does not establish a flicker-free condition.

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Modifiers, rigging and the working package

A discharge lamp needs the correct startup and operating procedure. Allow for stabilization and the documented restart conditions, particularly when a cue or schedule assumes immediate availability after power interruption. Inspect the lamp and complete head during prep.

The UV-protection glass and interlocks are essential operating parts. Do not bypass them or run the source with a damaged protection assembly. Isolate the system before lamp work and follow the manufacturer’s cooling and handling instructions.

The manual specifies 7m to illuminated persons, objects and surfaces, and 1m to flammable materials. Follow those manufacturer clearances for the documented configuration; a photometric table is not a separate clearance approval.

The head weighs approximately 11.5kg before its complete accessory and cable load. Use support appropriate to the assembled rig and account for the pull of the header cable. Keep the ballast separately supported, with a route that allows focusing and aiming.

IP23 is a limited weather-protection rating. Follow ARRI’s permitted orientation and operating conditions, and evaluate the ballast, connectors and distribution separately. A large diffusion frame or softbox also creates wind loading that the head’s IP rating says nothing about.

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Alternatives and related fixtures

Fixture	Choose it for
ARRI M-Series	Compare the exact lamp class, reflector and compatible ballast.
High-output LED spotlight	A different power, dimming and modifier system; compare coverage as well as centre lux.

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What people are saying

Meet the Gaffer: beam and power comparison

Luke Seerveld’s comparison meters the M18, M40 and Evoke 2400B, and examines shadows and power distribution. The chapters also include a correction concerning Constant mode on the LED fixture. View the source.

Videos

ARRI M18: family guide

Meet the Gaffer compares M18 and M40 with an Evoke 2400B; follow the stated optics and distances.

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Rental and used-fixture checks

Check the exact model and revision, complete power package, mounting hardware and control leads. Inspect lamp holders, protective glass and ballast connections. Test the intended operating level, fade and camera settings before rigging.

Documentation and specifications

Official specifications, accessories and downloads · Operating manual · ARRI Photometrics.

Product photograph: ARRI.

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