Canon Speedlite 600EX ii-RT Review

Canon 600EX II-RT Review

Front view of the Canon 600EXii-RT speedlite
Canon Speedlite 600EX ii-RT


The Canon 600EX II-RT Speedlite sits at the top of Canon’s range of flashes and has all the features that you’d expect from a quality bit of kit like this including a powerful performance, fast frame-rate shooting, wireless shooting via radio and optical transmission, 20-200mm zoom flash head, E-TTL II auto exposure control, high speed sync and an excellent infra-red auto-focus assist beam that supports up to 65 AF points. More importantly it is reliable, weatherproof and performs well in the most demanding of situations making it the top choice for event and wedding photographers. This is the speedlite that all other flashes are to be compared to but it comes with a hefty price tag especially when most professional photographers will want 2 or 3 of them!

Improvements over the previous Canon 600EX-RT version: The 600EX II-RT has faster continuous firing and up to 50% more flashes during high frame rate shooting. The improvement is credited to better heat dissipation and firing algorithms.

The Canon 600EX II-RT was released in May 2016

Guide Price

£519 / US$499 (updated 05 March 2021)

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


The Canon 600EX II-RT is compatible with all Canon EOS cameras allowing full E-TTL II auto exposure control. It uses Canon’s propriety 2.4GHz RT radio wireless system and can be used as a radio master for other speedlites such as the Canon 600EX ii-RT, Canon 600EX-RT or the Canon 430EX iii-RT. 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 an optical master or slave unit making it compatible with speedlites such as the Canon 580EX II, Canon 430EX II, Canon 470EX-AI, Canon 600EX ii-RT, Canon 600EX-RT, Canon 430EX iii-RT flashes as well as the Canon ST-E2 Speedlite Transmitter.

The Canon Speedlite 600EX ii-RT is also 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 Speedlite 600EX II-RT - rear view showing the control panel

Canon 600EX II-RT Specification


Maximum Guide Number 60m @ 200mm & ISO 100
Comparative Guide Number 34m @ 35mm & ISO 100
[60m@200mm, 57m@135mm, 54m@105mm, 39m@50mm, 34m@35mm, 28m@28mm, 27m@24mm, 26m@20mm, 15m@14mm]

Zoom Head

Zoom head: Yes
Focal length coverage: 20-200mm
Coverage with flip-down diffuser: 14mm
Auto zoom for sensor size: Yes
Flash bounce card: Yes

Flash Head Tilt & Swivel

Up: 45, 60, 75 and 90°
Down: 7° (for shooting close subjects in the range 0.5 to 2m)
Left: 60, 75, 90, 120, 150 and 180°
Right: 60, 75, 90, 120, 150 and 180°

Canon 600EX II-RT Speedlite - front view

Manual Exposure

Manual / output settings: Yes – 1/1, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128
Manual steps: 1/3 stop intervals

ETTL Exposure

Canon E-TTL II with flash exposure compensation (FEC), flash exposure lock (FE lock) and 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 over 360 degree range
No. of groups: 5 (A, B, C, D & E)
No. of channels: 15 channels and 10,000 wireless IDs
Master/Slave: Can act as both a master and a slave unit

Optical Wireless
Canon’s EX optical light pulse wireless system
Line-of-sight communication required.
Transmitter maximum range approximately: Indoors: 12-15m, Outdoors: 8-10m
No. of groups: 3 (A, B & C)
No. of channels: 4
Master/Slave: Can act as both a master and a slave unit

Auto-Focus (AF) Assist

AF-assist beam: Yes
Number of AF points supported: 1 to 65
AF-assist beam type: Infra-red
Beam range: 0.6-10m at centre, 0.6 to 5m at periphery

Canon 600EX II-RT - side view showing battery compartment

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: Yes
Colour temperature info communication: Yes
Remote shutter release: Yes
Custom function: 15 (6 personal functions) 
Flash settings from camera menus (with compatible cameras only): Yes
Optical slave capability (S1, S2): No
PC terminal: Yes
USB socket for firmware updates: No, there is no way to update the firmware

Batteries & Recycling Time

Battery: 4 x AA batteries (alkaline or rechargeable Ni-MH. Lithium not recommended)
Recycling time: Approx. 0.1 to 5.5 sec (I measured a 3 second recycle time at full power)
Number of flashes (approx): 100-700 with AA alkaline batteries
Flash duration: 1/890 to 1/34,000 sec
Flash Colour temperature: 5600K tbc
External power source socket: Yes, accepts Canon compact battery pack CP-E4N or the Godox PB960 Also compatible with the older Canon battery packs CP-E3 and CP-E4  (note: The PB960, CP-E3 and CP-E4 do not support the updated continuous, repeated flash firing of Speedlite 600EX II-RT, and are compatible for less-demanding flash firing applications only)

Canon 600EX II-RT - side view showing external battery socket and PC socket

Build Quality

Dust and water resistance: Yes
Mounting foot material: Metal
Size: 78.7 x 143.2 x 122.7mm (3.10 x 5.64 x 4.83″)
Weight: 435g/15.34oz (excluding batteries)

Included Accessories

Compatible accessories:


Canon 430EX iii-RT – At less than half the price the 430EX iii-RT offers a realistic alternative with only 2/3 stop less power.

Canon 580EX ii – A great alternative if you don’t need radio wireless. No longer in production but you can pick up some excellent bargains on ebay from time to time. If you need the radio wireless capabilities then you can just add a Yongnuo YNE3-RX radio receiver

Yongnuo 600EX-RT II – effectively a Canon copy for less than quarter of the price and uses the same RT radio wireless system so speedlites are compatible. Maybe not quite as reliable and not quite the same build quality or after sales support if anything goes wrong. I’m not as confident with the infra-red AF assist beam in low light.

Godox TT685 – Great alternative with similar spec but uses Godox X radio wireless system.

Canon 600EX II-RT Manual

Canon 600EX ii-RT manual download pdf format
Canon 600EX II-RT Manual pdf format (opens external link to Canon official website)

Canon 600EX II-RT User Guide

Under construction

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Page last checked and updated: 05 March 2021