Canon has announced an update to the Speedlite Transmitter ST-E3-RT, it’s called the ST-E3-RT (Ver.2). Launched back in 2012 this is the first update in almost nine years and adds features when it’s used with the latest cameras and Speedlite EL-1.

ST-E3-RT Ver.2, what’s new?

Second curtain sync flash – something Canon has never had before, though it’s available with independent flash systems.

FE memory – this lets you take a photo in E-TTL automatic flash then store the camera determined settings for use in manual mode

1/8192 power level setting when used with Speedlite EL-1 – you’re going to need the flash really close to the subject to benefit from this, maybe for macro setups.

Unfortunately you’ll need to be using one of the very latest cameras to take advantage of the new capabilities, that’s the EOS-1DX Mark III, EOS R5 and EOS R6 right now and they will need to be using the very latest firmware too.

For me the best bit of news is that my existing ST-E3-RT can be retrofitted with an update to give me the new features. Though it means it will have to take a trip to the Canon service centre to get it.

I’m intrigued to see how the 2nd curtain sync and FE memory options help with my Speedlite work. I know that the inexpensive Yongnuo YN-E3-RT II includes second curtain sync in manual mode, does the Canon also do it in E-TTL? Secondly I would like to see the FE memory function, it could be great with portrait setups but I wonder how or if it handles multiple off-camera setups. I’m certainly planning to get my ST-E3-RT updated.

Canon press release

Canon Europe announces the ST-E3-RT(Ver.2) – an update of the popular ST-E3-RT transmitter. Enabling wireless flash synchronisation and multiple control of Speedlites – positioned up to 30m away – this new transmitter gives professionals greater creative freedom in both a studio and natural environment. It supports key features of the recently introduced Speedlite EL-1 and also enables new capabilities when using previously launched RT Speedlites – including wireless (radio) second-curtain synchronisationᶦ.

Other new features of the ST-E3-RT(Ver.2) include support for the Speedlite EL-1’s low-power 1/8192 micro flashii, and for photographers who use manual flash, the transmitter boasts a new FE Memory mode.

High-quality, flexible capture

Through introducing radio wireless transmission and second-curtain synchronisationiii, the ST-E3-RT(Ver.2) releases the flash at the end of a long exposure. As a result, it helps photographers produce natural looking images when capturing moving subjects. The ST-E3-RT(Ver.2) offers this feature as a new wireless option, giving users flexibility in a range of shooting scenarios.

When shooting with a large aperture and/or high ISO speed, the flash level can often overpower the subject and scene. This forces the photographer to change settings or set up, ultimately losing the look they desired. When partnered with the Speedlite EL-1iv, the transmitter’s 1/8192 micro flash adds beautifully subtle nuances of light without disrupting the atmosphere and ambient light reflected on set. This feature is perfect for fashion and portrait photographers looking to capture scenes with a natural atmosphere.

Building on the original transmitter’s flexible qualities, the ST-E3-RT(Ver.2) supports FE Memory – offering a quicker and more convenient manual flash set up. Alleviating the need for multiple test shots, professionals now have the option to perform an initial shot in E-TTL mode, capturing the E-TTL flash settings. Users can then switch the Speedlites to manual flash to allow for manual adjustments where needed – all whilst retaining the original E-TTL settings.

Maximising product life span

Canon Europe is also providing a chargeable update for existing ST-E3-RT users. Those with the transmitter can send it to one of the listed Canon Service Centres to be upgraded to include the new additional features and capabilities of the ST-E3-RT(Ver.2).

For more information about the ST-E3-RT(Ver.2) and its compatibility, please visit:

About the author

Full-time photo tutor and photographer. I love to share my knowledge and skills to make photos, videos and teach others. I write books and articles for photo magazines and I always have at least one Speedlite flash in my camera bag