Some facilities will not allow you to use these items to take pictures of records in their custody–instead preferring you to have copies made at a per-page fee. Consider asking (nicely) if you can pay the same fee to take pictures of the items instead of making paper copies. Suggest that it’s easier on the records, uses less paper, etc. and that you are willing to have the staff watch as you take pictures.
These are things to find out before you arrive at the facility if at all possible.