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Why no 2nd curtain Sync on 600-RT speedlites? (Off-camera)


Nikon offers this, Why not on the newest canon speelites?

My Canon Prime Trinity + 24-105L
24L II - 50L - 135L

Rising Star

Good question. I wonder if Canon will respond to this. 


Take this with a grain of salt, I was under the impression there is a 2nd curtain setting, but only with optical, not with the radio portion. With radio you have high-speed sync.


I was quickly watching a tutorial video today and I thought that was how it was explained. I'm in the market for a speedlite and will decide which one to buy soon.


I to will be coming back to see what Canon says about this.


I have done some searches and although I have tried most everything myself I never tried second curtian sync, off camera, optical wireless with my 580's which I sold. So far I have read that optical wireless, off camera, second curtain sync is not possible wiht Canon is not possible. Something do the instruction order Canon has in their programming. I don't know if this applies to all Canon bodies but based on what I read I think it does. It appears Canon applied the same prgramming to RT. 





Bumping the thread because I wonder the same thing.

Here's my take...


Firstly there is no second curtain sync with either pulsed light or radio controlled off-camera flashes in the Canon system if you only use Canon kit.


I know for sure that Pocket Wizard can do it with the Flex / Mini devices added to the flashes. Maybe other 3rd party radio triggers too


In the pulsed light system the issue is that the command to "fire now" would need to be sent by pulsed light while the shutter is open, giving ghosting or potentially additional lighting to the scene. In the case of bulb mode for sure the camera won't know how long the shutter might be open before the flash is needed.


Over radio it should be possible, since the radio signal is not visible to the camera, and it's my request for Canon to add it to the radio system using 600EX-RT and ST-E3-RT via firmware update to flash or cameras.


Brian / p4pictures

Brian - Canon specialist trainer, author and photographer


I quizzed Canon on this some time ago, and received a standard 'technical issue' response. I didn't push them on it, because we both knew that that official line was in fact bunkum. The SCS function can be achieved with a software, firmware or hardware solution - not trivial, but definitely straightforward. 

Move on to a Canon evening at the Hollywood CPS facility some months back. There was a tech guy there who shall remain nameless, who revealed that it is almost certainly an oversight - a legacy from the optical system that the product development team neglected to include in the radio system.


Now, it may not be true, but this guy was close to the facts, and did seem rather embarrassed about it.



Hmm, so if this true I wonder if there is a way to update the firmware without sending a speedlite into Canon assuming someday there is an update. I know I'm getting way ahead, but has anyone ever recalled in the past a method where flash firmware can be field updated such as via a camera?

Since Canon has not replied since March that is a pretty good bet. If all it took was a Camera FM update they would have done it by now. I owned a Metz AF 58 at one time. It had a port so you could do FM updates. Very cool.   

Actually now that I think about thsi a good reason to come out with the ST-E3- RT II with second curtain sync, then the ST-E3-RT III with both SCS and AF assist and so on Man Tongue       

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