I am planning to upgrade my speedlight setup. Naturally, I stumbled upon Canon's
Speedlite 600EX II-RT, which offers 2 color filters (both CTOs) that will be detected by the flash.
The speedlight's manual states on p. 48:
By attaching the provided color filter to the flash, automatic correction is made by the camera's white balance function so that both the subject and background can be shot with appropriate white balance.
I also found out that Nikon's
SB-700 (and most likely other speedlights, too) supports this feature as "Color compensation filters", as described on p. E-21 of its manual:
When a color compensation filter is attached to the SB-700 while the camera's white balance is set to auto or flash, filter information is automatically transmitted to the camera, and the camera's optimum white balance is automatically adjusted to give the correct color temperature.
To me, this seems to implicate that the speedlight will tell the camera1 to not use the
flash preset for white balance, but to use a lower color temperature. So while great for shooting JPEGs, this seems to have no impact on shooting RAW (other than changing the initial WB value, which is something I almost always ignore, anyways), meaning that any speedlight with a regular CTO-gel would do just as well (from this perspective).
1 If the camera supports this speedlight-feature, of course.
Is my assumption correct or is there more to this feature?
Note that I am aware that custom gels could melt and are harder to fix on the speedlight than OEM filters.