ARRI True Blue ST2/3

Last Updated 11 hours ago

Overview

Key specifications

Specification	Details
Fixture type	Tungsten Fresnel
Lamp options	230V FKK 2,000W or HX48 3,000W, with the correct lamp holder and configuration
Lamp base	G38 on the current 230V product page; the family poster also lists G22/G38 variants
Operating voltage	220–240V for the ST2/3 configuration described here
Nominal colour	3,200K at the lamp’s rated operating voltage; dims warmer
Fresnel lens	250mm
Focus range	2kW lamp: 7.9°–56°; 3kW lamp: 11.6°–56.3°
Lamphead / version weight	10.5kg manual / 12kg pole-operated in the family poster
Mounting	28mm junior spigot
Scrim / barndoor	330mm / 344mm
Dimming / control	External tungsten-compatible dimmer; no internal DMX receiver
Protection	Class I; IP23
Dimensions (H × W × L)	522 x 448 x 380 mm excluding pin; product-page reference

Technical reference: ARRI specifications.

Strengths and limitations

• Strengths: a conventional focusable Fresnel field, a replaceable tungsten lamp and predictable warming during a dimmer cue.
• Trade-offs: substantial heat and electrical consumption for the light produced; no internal colour mixing, wireless receiver or electronic tint adjustment.

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Practical uses

Setup	Working approach
Studio key or side light	Use the 250mm Fresnel to cover a larger working area from a grid or perimeter position. Set the actual lamp and focus before choosing scrims or diffusion.
Warm motivated window	Aim from outside the playing area and use flags to control the patch on the set. A 2kW lamp and 3kW lamp cannot be assumed to give the same field or exposure.
Large bounce	Flood the head to cover the reflector evenly, allowing for the required source-to-surface clearance. Rig and control the bounce independently of the lamp.

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Output and colour

Lamp selection changes both power and focus range. ARRI’s ST2/3 product page identifies these separate optical configurations:

Approved lamp power	Published beam range
2,000W	7.9°–56°
3,000W	11.6°–56.3°

The ST-Series family poster includes a single ST2/3 illuminance column without identifying which of the two lamp powers produced those values. Confirm the lamp configuration before using that column for exposure planning. A 2kW lamp’s output should not be represented by scaling a 3kW figure, or by borrowing output from the smaller T2.

Tungsten produces a continuous spectrum, but its colour depends on filament temperature. Electrical dimming lowers output and warms the light. Use scrims, a suitable neutral-density arrangement or a change in distance when maintaining the lamp’s rated colour is more important than dimming from the console.

Correcting tungsten to daylight with full CTB costs a substantial amount of light. Compare the finished corrected source with an HMI or daylight LED at the subject, rather than comparing the uncorrected lamp’s wattage or peak lux.

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Power and lamp requirements

220–240V for the ST2/3 configuration described here. Fit a lamp whose voltage, wattage, base and approved operating position match the specific head. A 120V lamp must not be connected to a 230V supply simply because a family listing covers both markets.

These are resistive tungsten loads controlled from a suitable supply and external dimmer, without an HMI ballast. The lamphead does not contain an auto-ranging LED power supply. The connector, cable, dimmer and distribution must be rated for the fitted lamp.

At 230V, the nominal steady-state calculation is about 8.7A for a 2,000W lamp and 13.0A for a 3,000W lamp. These P ÷ V values are calculations, not circuit ratings; dimmer capacity, cold-filament inrush and the complete distribution still determine the operating package.

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Control, cooling and camera operation

Intensity is controlled by the external dimming system. A DMX dimmer rack can provide console control, but a DMX cable does not connect directly to this lamphead. Focus, tilt and barn-door shaping remain mechanical.

Keep the ventilation path open and leave room for hot air around the head. The fixture itself has no cooling fan; vibration, filament noise or the external dimmer can still be relevant on a quiet stage. Check any visible flicker at the intended shutter and frame rate.

Manual and pole-operated versions differ in the yoke and available pan/tilt operation. Pole operation does not add motorized focus or an internal wireless control system. Confirm the actual model rather than assuming all ST heads in a rental inventory have the same controls.

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Modifiers, rigging and the working package

Item	What to specify
Front accessories	330mm scrims and 344mm barn-door reference for this head. Similar wattage does not guarantee a matching accessory frame.
Soft light	Use a heat-rated, explicitly compatible bank or a separately supported bounce/diffusion frame. Include the correct speedring where required.
Support and clearance	Choose the support for the head, front accessories and leverage at the required tilt. Keep the supply cable clear throughout movement.
Lamp and spares	Include the correct lamp code and voltage, any required adapter, and an appropriate spare for location work.

ARRI’s family reference specifies a minimum 4m to the illuminated surface and 1m around the fixture. The current lamphead label and manual control the actual installation. Keep hot-light accessories clear of the lamp and allow cooling before handling or packing.

The ST2/3 is a distinct lamphead supporting specified 2kW/3kW configurations. The ST1/2 Theater is a separate theatre fixture with a different lens and cassette arrangement; it should not be substituted under this model name.

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Alternatives and related fixtures

Fixture	Why compare it
ARRI True Blue T2	A related head with a different lens, power class or optical design; compare the actual modifier, output and support package.
ARRI Orbiter	Colour-tunable LED control and an interchangeable optical system where heat, mains load or rapid colour changes drive the choice.
ARRI L7-C Plus	A focusable full-colour LED Fresnel for lower-power studio work and electronic colour control.
ARRI True Blue ST1	A smaller 1kW studio Fresnel when the lens size and working output suit the position.
ARRI True Blue ST5	A larger 5kW studio head with a 300mm lens and different support and power demands.

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Manufacturer and handling notes

ARRI’s ST-Series presentation shows the studio family and its handling features. When comparing a rental package, the useful distinctions are the actual manual or pole-operated yoke, front accessory sizes and lamp configuration. Manufacturer demonstrations should be read alongside the exact-model tables rather than treated as independent output tests.

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Videos

ARRI: introducing the True Blue ST Series. Manufacturer family demonstration covering studio Fresnel handling.

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Rental and used-fixture checks

• Check the lamp code, voltage, wattage and lamp-holder configuration against the actual fixture label.
• Inspect the lens or protective glass, mesh, reflector, holder and front latch; reject cracked protection or heat-damaged wiring.
• Run the full focus and tilt range, then check the lock with the intended front accessories fitted.
• For a pole-operated head, test the pan and tilt controls under the conditions in which it will hang.
• Check the cable, connector, earth continuity and external dimmer through the rental house’s normal electrical inspection; include a spare lamp and cooling time in the package.

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Documentation and specifications

• ARRI True Blue ST2-3 specifications and downloads
• ARRI True Blue ST & ST Theater – Overview Poster
• ARRI True Blue T1, 2, 5 and ST 1, 2, 2-3, 5 – Manual

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