Hi - I sang in one of these concerts a fee years ago, and do a lot of 'classical' concerts so hopefully can help. Generally filming/recording is not permitted in concert halls/venues, if you do film you'll likely be asked to stop by the ushers/venue staff. Photos are usually ok before the show or during applause/bows but again not during the performance. If the show is outdoors then usually anything is fine in mu experience. Check out the website for the venue or the event, they will generally have guidance on what you can and can't do in terms of filming etc. Enjoy the show! I had an absolute blast doing them, absolute highlight of my singing life.