Yes. Canon also has a near-infrared proprietary optical system for wireless flash. It doesn't have a snazzy marketing name like CLS, but is often referred to as "Canon wireless eTTL" or "Canon optical slaving". Like CLS, it can communicate most of the full hotshoe protocol, such as eTTL-II and high-speed sync (HSS). It also allows for control of the remote flash through the camera's flash control menu, if the camera is Digic IV or later and has the menu and the flash is an EX MkII or EX-RT unit. Post-2012 Canon bodies have a flash control panel that shortcuts all the settings, without as much menu diving.

Canon speedlite units that can be used as masters in this optical system are:

• 550EX
• 580EX / 580EX II
• 600EX-RT / 600EX II-RT
• 90EX
• ST-E2 (master only; no flash head)
• MR-14EX / MT-24EX

Canon units that can be used as slaves in this optical system are:

• 270EX II
• 320EX
• 420EX
• 430EX / 430EX II / 430EX III-RT
• 550EX
• 580EX / 580EX II
• 600EX-RT / 600EX II-RT

There are, however, some differences from CLS. There is no equivalent of the SU-4 "dumb" optical slave mode. And unlike CLS, wireless 2nd-curtain sync is not possible with the Canon system. And Canon not only has an optical-based system, but also a radio-based one. The "RT" system, however, consists of only four units at this time (600EX II-RT, 600EX-RT, 430EX III-RT, and ST-E3-RT) and there are no built-in radio masters in any camera body.

Canon camera bodies that have optical masters in the pop-up flash are:

• 600D and later xxxD models
• 60D and later XXD models
• 7D and later 7D models

However, the pop-up flash masters are not capable of HSS or communicating wireless HSS to slave flashes.

This optical system can allow up to three groups (A:B:C), depending on the gear (e.g., a 550EX can only master groups A:B with ratios), and power control is either by ratios, or by ratios or manual power level settings.

In 2012, when Canon's "RT" system arrived, a number of enhancements were made to the camera/flash communication. Obviously, you also need a 2012 or later body as well as Canon's RT flashes to use these additional features that are NOT part of the optical system:

• 4-digit ID code, which with channel settings, allows for thousands of discrete channels
• Remote shutter control over the camera from the flash.
• Groups D and E.
• Gr mode (i.e., groups can now independently be set to MULTI, eTTL-II, or M modes as well as turned on and off)
• Radio communication (enhanced range and no line-of-sight requirements).