Notice Regarding Firmware to Fix Phenomenon in Linked Shooting and Wireless Flash Shooting (During Use With 7 or More Units) When Using the Canon Speedlite 600EX-RT and Speedlite Transmitter ST-E3-RT
Thank you for using Canon products.
Phenomena
Except as described below, the following will occur with the affected units listed below:
Linked shooting and wireless flash shooting with radio transmission will not work in some setting modes when 7 or more units are linked. This phenomenon does not occur when 6 or fewer units are linked.
Affected Products
Speedlite 600EX-RT and Speedlite Transmitter ST-E3-RT
Units with a combination of 3rd and 4th digits in the serial number in the ranges shown below are affected.
| Speedlite 600EX-RT: | [xx01xxxxxx] ~ [xx12xxxxxx] |
| Speedlite Transmitter ST-E3-RT: | [xx01xxxxxx] ~ [xx03xxxxxx] |
Note: If the battery compartment of an affected unit contains the marking illustrated below, the product is NOT affected by the phenomenon described above, even if the serial number is within the ranges mentioned above.
 |  |
| Speedlite 600EX-RT | Speedlite Transmitter ST-E3-RT |
Market Support
To arrange to have an affected unit inspected and serviced for this phenomenon at no cost, please contact your nearest Canon Service Center.