I'm not sure which concert you are attending; however, in pretty much all instances the venues state "no photos, camcorders, recorders, etc etc etc". However, Leonard's management has a rather ambivalent stand on this. I would say feel free with the photos etc... Just make sure the flash is OFF. That is irritating to fellow fans and VERY irritating to those on stage. Simply be discreet and enjoy the concert totally!
You have only to check out YouTube to see how many concerts were filmed, and many concerts have been quietly recorded in their entirety!
Welcome to the Forum; and enjoy what I know will be an awesome concert!
All the best,