I switch this flash from standalone mode to slave mode, depending on what I’m doing. Fortunately it’s easy to make that change. Speedlite ST-E2 (bought January 2011) I use this mainly to control the 580EX II and 600EX-RT flashes, but sometimes use it standalone if I want the autofocus assist light.
https://www.amazon.com/Canon-Speedlite-580EX-Digital-Cameras/dp/B000NP3DJW