Hot-air balloons are expensive flying machines and require endless maintenance. Those who fly them must be properly qualified as hot-air balloon pilots, not only for the safety of themselves and their passengers but also for the safety of other aircraft and aviators. Balloons are often operated by small teams of people who share costs, flying opportunities, launch and recovery duties and other maintenance work. Others are sponsored by large companies who use balloons as advertising media. A photographer who wishes to work from a hot-air balloon cannot therefore expect to arrive at a launch site and request a flight.
One approach to finding an occasional flight would be to join a club or a balloon team, working initially in a ground support role. After a period in such a role it might be reasonable to request a flight, but remember that each flight costs money and can carry only a certain number of passengers. The presence of a photographer deprives someone else of a flight. Another approach, and perhaps the most practicable one, is to pay someone who operates a balloon for an aerial photography flight over a particular area. Indeed there are numerous companies that operate commercial balloons to satisfy the demand for pleasure flights.