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Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module for Godox

BH #SEL858DUSMG • MFR #401-858GX
111 reviews
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Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module for Godox
Key Features
  • Speedmaster L-858D-U Light Meter
  • RT-GX Godox Transmitter
Improve flash metering efficiency and accuracy with this Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module, which pairs the advanced L-858D-U light meter with the RT-GX Transmitter Module for wireless radio control via the Godox triggering protocol.
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Expected availability: Jan 27, 2025
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Sekonic L-858D-U Overview

Improve flash metering efficiency and accuracy with this Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module, which pairs the advanced L-858D-U light meter with the RT-GX Transmitter Module for wireless radio control via the Godox triggering protocol.

Sekonic Speedmaster L-858D-U Light Meter

Aiming to provide for the needs of both photographers and filmmakers, the Speedmaster L-858D-U Light Meter from Sekonic comes packed with a variety of upgraded features and capabilities that make it an almost essential tool for a working professional. It is able to take incident and reflected light readings of both flash and ambient light with an expanded measuring range of -5 to 22.9 EV at ISO 100, or within an illuminance range of 0.1 to 2,000,000 lux. Users will also find it intuitive and easy-to-use thanks to the use of a 2.7" color touchscreen LCD and an all-weather design.

The meter can use either a 270° rotating and collapsible lumisphere or an integrated 1° spot viewfinder to account for varying needs of the user. Also, it offers an extensive range of cinema and video settings as well as the unique ability to measure flash duration and to take readings when using high-speed sync flash. The L-858D-U is equipped with a variety of other functions as well, including memory recall, a Flash Analyzing Function, and extended ranges on nearly every setting. Additionally, through the use of optional modules, users can add radio triggering support for PocketWizard and Elinchrom/Phottix systems.

Lumisphere receptor head rotates 90° right and 180° left and retracts for conversion to a flat diffuser.
Integrated 1° spot viewfinder with full information display provides a precise method of measuring specific parts of a scene.
Ability to measure flash duration within a range of 1/40 to 1/55,500 second using t0.1 to t0.9 settings.
Improved sensitivity of the L-858D-U allows it to record a reading at just 0.1 lux illuminance as well as use expanded range of -5 to 22.9 EV for incident readings and -1 to 22.4 EV for reflected light. Also, it features an extended ISO range of ISO 3 to ISO 13,107,200 with an option available for ISO 850.
Optional radio modules are available for PocketWizard and Elinchrom/Phottix systems for advanced wireless triggering and remote flash control.
High-Speed Sync support allows photographers to accurately take readings while using HSS with their flashes and cameras.
Flash Analyzing Function measure ambient and flash simultaneously to provide a percentage of flash in the final exposure. Users can then adjust the mix as the display shows camera settings and the relationship between the flash and ambient light in your exposure.
Users can determine the dynamic range of their camera using optional targets by taking bracketed shots with their measurement data and they using the Sekonic Data Transfer Software to graph and then save the information to the meter.
Expanded shutter speed ranges now allow for readings between 1/64,000 second to 30 minutes with ambient light and 1/16,000 second to 30 minutes for flash.
A comprehensive set of cinema modes allows for settings of 1-1000 fps as well as shutter angles of 1-358°. Twenty user determined settings are also available that provide more precise options of 0.001-360° shutter angles and 0.001-99,999.999 fps.
2.7" color touchscreen LCD provides a fast and intuitive method for viewing and changing settings.
Micro-USB port can be used for firmware updates, applying custom settings, and to use exposure profiling.
The L-858D-U features an all-weather construction that is dust and splash proof (JIS Class 4).
Sekonic RT-GX Godox Transmitter Module

Add a 2.4 GHz Godox-compatible radio triggering protocol to your Speedmaster L-858D-U light meter with this RT-GX Godox Transmitter Module from Sekonic. Able to be fitted into meter's housing, this module provides multiple functions beyond triggering, including access to 32 channels and up to 16 groups and Wireless IDs for remote triggering within a 98.4' range. This radio control also permits adjusting the modeling light power, supports high-speed sync (HSS) flash metering, and enables Godox users to more easily measure the ambient-to-flash light ratio and flash duration.

Sekonic L-858D-U Specs

Key Specs
Meter Type
Ambient, Cine, Flash, Spot
Spot Metering
1° Spot
Flash Metering
Cordless
Light Reading Method
Incident, Reflected
Light Readings
Candelas per Meter Squared (cd/m²), Foot Lamberts (fl), Footcandle, Lux
Measuring Modes
Aperture Priority, FPS Metering, Flash Duration Analysis, HSS Flash, Shutter Priority
Max Flash Sync Speed
1/16,000
Cine Speed / Shutter Angle
0.001 to 1000 fps at 1 to 358°
Diffuser
Adjustable Spherical to Flat
Display
2.7" / 6.9 cm Color Touchscreen LCD
System Connection
PC Sync Terminal
Micro-USB Port
Battery
2x AA (Alkaline, Manganese)
Radio System
No
Spot Metering
1° Spot
Flash Metering
Cordless
Metering
Light Reading Method
Incident, Reflected
Light Readings
Candelas per Meter Squared (cd/m²), Foot Lamberts (fl), Footcandle, Lux
Measuring Modes
Aperture Priority, FPS Metering, Flash Duration Analysis, HSS Flash, Shutter Priority
Aperture Range
Flash, Incident: f/0.5 to 128.9 at ISO 100
Flash, Reflected: f/1 to 128.9 at ISO 100
f/0.5 to 161.2 (1, 1/2, 1/3-Step Increments) at ISO 100
EV Range
Ambient, Incident: -5 to 22.9 EV at ISO 100
Ambient, Reflected: -1 to 24.4 EV at ISO 100
ISO Range
3 to 13,107,200 (1/3-Step Increments), Plus 850
Shutter Speed Range
1/64,000 to 30 Minutes (1, 1/2, 1/3-Step Increments), Plus 1/400, 1/200
Max Flash Sync Speed
1/16,000
Cine Speed / Shutter Angle
0.001 to 1000 fps at 1 to 358°
Illuminance Range
0.1 to 2,000,000 Lux / 0.01 to 180,000 fc
Luminance Range
0.3 to 290,000 fL / 0.1 to 980,000 cd/m²
Exposure Memory
Yes, 9 Readings
Physical
Receptor Element
Silicon Photodiode
Diffuser
Adjustable Spherical to Flat
Display
2.7" / 6.9 cm Color Touchscreen LCD
System Connection
PC Sync Terminal
Micro-USB Port
Media Card Reader
No
Tripod Mounting Thread
1/4"-20 Female
Environmental
Operating Temperature
14 to 122°F / -10 to 50°C
Operating Humidity
0 to 85%
Storage Temperature
-4 to 140°F / -20 to 60°C
Storage Humidity
0 to 85%
General
Battery
2x AA (Alkaline, Manganese)
Radio System
No
Dimensions
3.7 x 6.9 x 1.9" / 94 x 176 x 49 mm
Weight
8.5 oz / 240.0 g (without Batteries)
Packaging Info
Package Weight
1.395 lb
Box Dimensions (LxWxH)
10.3 x 6.55 x 3.8"

Sekonic L-858D-U Reviews

See any errors on this page? Let us know

Does this meter also meter non radio transmitter ...

Does this meter also meter non radio transmitter flashes?
Asked by: Ira
Certainly. You could either use cordless flash mode (light meter waits up to 90 seconds for a pop of flash) or synchro-cord mode (wired light meter to your flash via sync cable). For more info, check out page 73 of the manual here: https://www.bhphotovideo.com/lit_files/474654.pdf
Answered by: Jeremy
Date published: 2020-12-27

Is there a way to display the continued ...

Is there a way to display the continued measurements in the 1-Degree Viewfinder Spot using the L-858D-U-U light meter as Sekonic L-758DR Spot meter does?
Asked by: Willian
Yes, you can display continued measurements in the 1-Degree Viewfinder Spot on the Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module for Godox.
Answered by: Rob K
Date published: 2022-06-07

when you have a Godox XPro F TTL trigger on the ...

when you have a Godox XPro F TTL trigger on the camera but using the Sekonic to dial in the lights, does the trigger on camera automatically adjust, or reflect your changes you made on the Sekonic? Or do you have to hit some button on the trigger to reset/refresh every time? And if once you're shooting you notice one light needs to be dialed up or down, can you adjust from the trigger on camera and will the Sekonic adjust the value as well? Just wondering so that during a shoot it's not too confusing.
Asked by: Ron
I contacted Sekonic regarding your inquiry. According to Sekonic, they state you will need to place the Godox transmitter in App mode. Go to [Menu], shoot and then select [App}. This would put the transmitter into trigger only mode so it will not effect the setting made by the Sekonic meter.
Answered by: Manzell L
Date published: 2020-12-05

I have an issue with the L-858D-U with Godox ...

I have an issue with the L-858D-U with Godox transmitter kit. When I switch it on I get an error message, "Radio Transmitter Installed Cannot Be Used In This Meter". I have already sent a copy back for having the same issue. Am I missing an obvious set up step? As it is sold as a kit and the transmitter is already installed in the unit I am surprised that it doesn't work straight out of the box.
Asked by: Paul
This is a known issue that will be remedied by updating the firmware.
Answered by: Luis L
Date published: 2020-11-20

When using the flash in hss mode at a certain ...

When using the flash in hss mode at a certain power output level for example at 1/2 power lever, then if i press the test flash button from trigger and measure with seconic light metre, the meter will show the camera setting for 1/2 power flash output in normal setting but not in hss mode. but power of a flash is normally lower in hss mode than in normal mode. with the transmiter of this seconic light meter, if we press the test button can it give us the correct camera setting in hss mode or we have make a test shot from the camera?
Asked by: Mohammad Bayzed
According to Sekonic, they state that when measuring HSS output, the camera has to be test-fired, meaning you have to press the shutter button on the camera (or use a remote release to trigger the shutter). Using the [TEST] button on the flash will not work when attempting to record HSS output for exposure purposes.
Answered by: Manzell L
Date published: 2021-01-06

Will L 858D-U work outside US as I would be ...

Will L 858D-U work outside US as I would be travelling for work often?
Asked by: Sanjay
Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module for Godox does work outside of the USA.
Answered by: Daniel C
Date published: 2022-01-13

Will this work with the Godox X3 trigger?

Will this work with the Godox X3 trigger?
Asked by: Khody
If you are using the Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module for Godox, you would not need the Godox X3 Trigger. The Sekonic L-858D-U Speedmaster Light Meter Kit with Transmitter Module for Godox would communicate directly with Godox off-camera strobes that have a built-in Godox X-wireless radio receiver.
Answered by: Andrea B
Date published: 2024-12-18

I just bought the exposimeter with the godox ...

I just bought the exposimeter with the godox transmitter, is it possible to change the transmitter later?
Asked by: Kevin
The transmitter module can be substituted with a different module , usable for other lights , at additional cost
Answered by: Shalom
Date published: 2023-02-06
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