The built-in flash automatically fires even without being previously set. (EOS REBEL SL1 / EOS 100D)
21-Mar-2013
8201787500
Solution
In the < 
> (Scene Intelligent Auto), < 
> (Creative Auto), <
> (Kids), < 
> (Portrait), < 
> (Close-up), or < 
> (Night Portrait) mode, the camera automatically judges the shooting environment to determine whether the built-in flash fires or not. Therefore, the built-in flash may automatically fire in low-light environments even if you do not want to use it.
> (Scene Intelligent Auto), < > (Creative Auto), <> (Kids), < > (Portrait), < > (Close-up), or < > (Night Portrait) mode, the camera automatically judges the shooting environment to determine whether the built-in flash fires or not. Therefore, the built-in flash may automatically fire in low-light environments even if you do not want to use it.To prevent the built-in flash from firing automatically, change the shooting mode.
For more details, see the built-in flash section of List of functions that can be set in each shooting mode (EOS REBEL SL1 / EOS 100D).