The Public Transport C of A merely indicates the type of maintenance schedule and the level of qualification of the Maintenance Organisation that is allowed to perform the C of A. Also, the aircraft may feature on any number of AOC's, but can also be used for Aerial and other work outside an AOC (like for private, non-hire use). Providing no paying passengers (or cargo) are carried, photography is Aerial Work. But I'd suggest that it would get a little grey if the person commissioning the pictures comes along to "supervise".