Sekonic SpeedMaster L-858D + RT-GX Transmitter Module Bundle Kit

  • RT-GX Transmitter module for Godox/Flashpoint is built-in the meter
  • Incident Metering for Ambient & Flash
  • 1° Spot Metering with Viewfinder
  • Measuring Range: EV-5 to EV22.9 (ISO 100)
  • Illuminance Range: 0.1 lux to 2,000,000 lux
  • Extensive Range of Cine & Video Settings
  • HSS Flash & Flash Duration Measurements
  • Flash Analyzing Function; Extended Range
  • 2.7″ Touchscreen LCD; All-Weather Design
product description


With it’s 2.7” color touch screen and truly innovative and sophisticated features, the Sekonic Speedmaster L-858D leads the way to the next generation of light measurement control as the world’s first multi-function light meter for photographers and filmmakers. Leveraging over 60 years of experience in the image-making world with cutting-edge technology, the Sekonic Speedmaster L-858D has undergone a significant design change and boasts a comprehensive feature set sure to meet and exceed the demands of today’s photographers and filmmakers.

The first meter of its kind capable of measuring flash duration, while also being able to achieve an accurate ambient exposure reading in dimly lit scenes as low as 0.1 lx, the Sekonic L-858D provides image-makers of all levels with the critical exposure data they need to create stunning and beautiful imagery.

The first to provide wireless compatibility with Godox/Flashpoint products (Replacable with broncolor, Elinchrom, Phottix and PocketWizard transmitter sold as separately), the Sekonic Speedmaster L-858D also provides ultimate control to photographers seeking a faster and more streamlined workflow. Limitless creative possibilities are within reach through the meter’s ability to measure High Speed Sync (HSS) and calculate proper ambient-flash exposure for precision flash exposure control.

With an increased light-sensitivity and extended ISO and Shutter Speed Ranges, the Sekonic Speedmaster L-858D enables all image-makers to obtain measurements in extremely low light and turn those readings into creative decisions. Finally, matching the high-ISO capabilities of today’s cameras, by accurately metering in low-light, is finally possible.


Sekonic Transmitter Module RT-GX for L-858D Speedmaster light meter. Used to trigger Godox/Flashpoint enabled lighting and receivers.

Triggering and controlling the power level of Godox 2.4GHz wireless X system and Flashpoint 2.4GHz system built-in flash units
Modeling lamp output power control with ON/OFF
Wireless ID: (1 to 99 or OFF)
Channel: 32 (CH1 to 32)
Group: 16 (A to F, 0 to 9) + ALL
HSS (High Speed Synchro) flash radio triggering is available