The 430EX III-RT becomes the second Canon Speedlite to feature radio triggering, following the 600EX-RT. Unlike the 600EX-RT, however, the new 430EX III-RT cannot function as a master flash in a multi-flash setup. It will only serve as a slave to be triggered by the 600EX-RT or the ST-E3-RT Speedlite transmitter.
Canon says the new flash has shorter recycling time for quicker firing and it is smaller and lighter than its predecessor. The 430EX III-RT comes with an color filter for balancing color temperature when shooting in tungsten lighting. It also includes the SBA-E2 bounce adapter and built-in catchlight panel.
The flash has a maximum Guide Number of 43/141 at ISO 100 in meters/feet, auto zooming from 24-105mm, Hi-Speed Sync and Second-curtain Sync.
The Canon Speedlite 430EX III-RT retails for $299.99 and should be available in September 2015. Check it out here at B&H Photo.