The Canon ST-E3-RT was released in 2012 and is Canon’s only dedicated radio transmitter which works using their 2.4GHz RT radio system. The transmitter can be used as a master to control the Canon 600EX II-RT, 600EX-RT and 430EX III-RT speedlites. The transmitter supports E-TTL II and high speed sync and has a range of up to 30m. It hasn’t been upgraded since it was released but it still works fine with all the most recent Canon speedlites and cameras so that’s not a problem.
Yongnuo YN-E3-RT II
The Yongnuo YN-E3-RT II is Yongnuo’s latest version of radio transmitter and was released in December 2018. As you can see in the photos it’s an almost exact copy of the Canon model. It uses the same RT radio system and is directly compatible with the Canon 600EX II-RT, 600EX-RT and 430EX III-RT speedlites. The Yongnuo transmitter also supports E-TTL II, high speed sync and has all the other functions the Canon transmitter does plus a few extras for good measure. It has a longer range of up to 100m (instead of 30m) and it has an auto-focus assist lamp which sends out a powerful infra-red beam of light that helps the camera to focus on the subject in low light conditions. This is a definite plus point and can be really useful on occassions. The Yongnuo also has a micro-USB port to allow firmware updates.
Canon ST-E3-RT vs Yongnuo YN-E3-RT II
Canon ST-E3-RT Good Points
- Reliability and compatibility
- Weather sealed
Canon ST-E3-RT Bad Points
- No AF assist
- 30m range
Yongnuo YN-E3-RT II Good Points
- USM port for firmware updates
- 100m range
- AF assist beam
Yongnuo YN-E3-RT II Bad Points
- Build quality and weather sealing not quite as good as the Canon but more than adequate for most situations.
Canon ST-E3-RT vs Yongnuo YN-E3-RT II? Well if money was no problem I’d buy one of each and use my Canon transmitter for most of my work and keep my Yongnuo transmitter as a backup or to use when I particularly needed the AF assist beam. If you only have Canon speedlites then I think it’s wise to pay the extra and go with the Canon version knowing that it will be future proofed if I upgrade my camera. I’m never had a problem with the 30m range of the Canon transmitter. If you only have Yongnuo speedlites then buying the Yongnuo version makes more sense. Hopefully a firmware update will allow compatibility with future Yongnuo speedlites.