if at all the camera flashed, there will be either no fine or a maximum of 500, depending on how you crossed and then reversed; but most likely there will be no fine; they have video reviews these days of the violation before they issue the fine so if you stopped safely, they mostly let it go... don't worry, max is 500 and that's unlikely; and please remember to come back here and update the post with what happened; it can help others like you in future so don't just get our opinions and then disappear and leave behind a useless post where three of us have given you three slightly different answers; you have to come back and leave the correct answer for the next guy in this situation :-)