Canon Speedlite 430EX iii-RT Review

Canon 430EX III-RT Review

Canon 430EX iii-RT
Canon 430EX iii-RT


The mid-range Canon 430EX III-RT Speedlite improves on the previous model with the introduction of radio-based wireless E-TTL II communication. This speedlite can now be used as both radio master and radio slave. Optical wireless slave transmission has still been retained for greater compatibility but it can only be used as a slave unit in optical wireless mode. The 430EX III-RT boasts a very respectable guide number of 43m (@105mm & ISO 100) along with a zoom range of 24-105mm and a flip-down wide panel that extends coverage to 14mm. Bounce has been expanded with the ability to rotate 150° right and 180° left as well as tilt upwards 90°. Enhancing operations are a larger dot-matrix LCD screen and a multi dial for smooth manoeuvring of the menu settings.

All in all, on or off camera the 430EX III-RT is a very capable tool and, at around half the price of the Canon 600EX II-RT and only 2/3 of a stop less powerful this lightweight, more compact model offers great value for money.

The Canon 430EX III-RT was released in July 2015.

Guide Price

£273 / US$299 (updated 05 March 2021)

Wex (UK) / Amazon (UK) / B&H Photo (US) / Adorama (US) / Amazon (US)


The Canon Speedlite 430EX iii-RT is compatible with all Canon EOS cameras allowing full E-TTL II auto exposure control. The 430EX iii-RT uses Canon’s propriety 2.4GHz RT radio wireless system and can act as a radio master for the Canon 600EX ii-RT, Canon 600EX-RT or Canon 430EX iii-RT flashes. It can also act as a radio slave for the Canon 600EX ii-RT, Canon 600EX -RT, Canon 430EX iii-RT flashes as well as the Canon ST-E3-RT Speedlite Transmitter.

This speedlite also retains the Canon EX optical wireless system and can be used as a optical slave-only unit able to receive commands from the Canon 580EX II, Canon 580EX, Canon 600EX ii-RT and Canon 600EX-RT flashes as well as the Canon ST-E2 Speedlite Transmitter.

The Canon Speedlite 430EX iii-RT is also fully compatible with some third party speedlites made by Yongnuo such as the Yongnuo 600EX-RT II. See Yongnuo’s range of speedlites for more details.

Canon 430EX III-RT Specification


Maximum Guide Number 43m @ 105mm & ISO 100
Comparative Guide Number 28m @ 35mm & ISO 100
[43m@105mm, 41m@80mm, 40m@70mm, 33m@50mm, 28m@35mm, 24m@28mm, 22m@24mm, 14m@14mm]

When compared to the Canon 600EX ii-RT the Canon 430 iii-RT is about 2/3 of a stop less powerful at 35mm (GN28m v GN34m @ 35mm & ISO 100)

Zoom Head

Zoom head: Yes
Focal length coverage: Auto, 24-105mm
Coverage with flip-down diffuser: 14mm
Auto zoom for sensor size: Yes
Flash bounce card: Yes

Canon Speedlite 430EX III-RT - rear view showing the control panel

Flash Head Tilt & Swivel

Up: 45, 60, 75 and 90°
Down: No
Left: 60, 75, 90, 120, and 150°
Right: 60, 75, 90, 120, 150 and 180°

Canon Speedlite 430EX III-RT - side view

Manual Exposure

Manual / output settings: Yes – 1/1- 1/128
Manual steps: 1/3 stop intervals

ETTL Exposure

Canon ETTL with flash exposure compensation (FEC), flash exposure lock (FE lock). There is no flash exposure bracketing (FEB) 

Wireless Communication

Radio Wireless (RF) 2.4GHz
Uses Canon’s 2.4GHz RT radio system.
Transmitter maximum range approximately: up to 30m
No. of groups: 5 (A, B, C, D & E)
No. of channels: Auto, 15 channels and 10,000 wireless radio IDs
Master/Slave: Can act as both a master and a slave unit

Optical Wireless
Line-of-sight communication. 
Transmitter maximum range approximately: Indoors: 12-15m, Outdoors: 8-10m
No. of groups: 3 (A, B & C)
No. of channels: 4
Master/Slave: Slave only when using optical wireless

Canon Speedlite 430EX III-RT - back view showing the control panel lit up in radio slave mode
In slave mode the display light is orange

Auto-Focus (AF) Assist 

AF-assist beam: Yes
Number of AF points supported: 1
AF-assist beam type Infra-red / flash strobe
Beam range (when using infra-red): 0.7-8m at centre
Beam range (when using flash strobe: 0.7-4m at centre. 0.7-3.5m at periphery

front view

Other Features

High speed sync (HSS): Yes
Second-curtain flash sync: Yes
Modelling flash: Yes (fired with camera’s depth-of-field preview button)
Multi (stroboscopic) flash: No. The 430EX III-RT doesn’t have the stroboscopic flash feature when used alone, but it does support the feature when used in slave mode with a master that has the feature. 
Colour temperature info communication: Yes
Remote shutter release: Yes
Custom function: 10 (8 personal functions) 
Flash settings from camera menus (with compatible cameras only): Yes
Optical slave capability (S1, S2): No
PC terminal: No

Batteries & Recycling Time

Battery: 4 x AA batteries (alkaline or rechargeable Ni-MH. Lithium not recommended)
Recycling time: Approx. 0.1 to 3.5 sec
Number of flashes (approx): 180-1200 with AA alkaline batteries
External power supply: No

Build Quality

Dust and water resistance: No
Mounting foot material: Metal
Size: 70.5 x 113.8 x 98.2mm (2.78 x 4.48 x 3.87″)
Weight: 295g/10.41oz (excluding batteries)

Canon Speedlite 430EX III-RT - side view showing battery compartment

Included Accessories

Compatible accessories: 


Canon 430EX II Speedlite – basically the same model without the radio wireless. No longer in production but excellent bargains can often be found on ebay.

Canon 430EX III-RT Manual

Canon 430EX III-RT manual download pdf format
Canon 430EX III-RT Manual pdf format (opens external link to Canon official website)

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Page last checked and updated: 05 March 2021