Is it acceptable to place a note in the wedding invitation to tell guests not to take photographs at the wedding ceremony?
As a general wedding guideline, it is best to keep the wedding invitation focused on your wedding details (ie. date, time, location, etc.).
There are different ways you can let wedding guests know not to take photos at the wedding ceremony, without involving the wedding invite.
If your wedding ceremony is at a church, often times, the minister/officiant will let you know in advance that flash photography is not permitted during certain times of the wedding ceremony as it detracts from the event. If you haven’t done so yet, do chat with your minister/officiant about this. He/she will most likely make an announcement before the ceremony for flash photography NOT to be taken at specific times. It’s also a great time to remind guests to turn off their cell phones.
You can also enlist the help of friends on the day of the wedding. As they hand out wedding programs, etc. have them remind all guests individually as they enter the space not to use flash photography. It is best not to single out any one individual. The personal contact will help to emphasize your wishes.
At the end of the day, while it may be your wedding, you will only have limited control over what happens. Someone will inevitably cough, sneeze, or flash their camera at the most unexpected time with the best of intentions. Having said all that, there are different techniques to encourage guests to see your point of view.