Hi there! So, you want to have a photography policy. You're holding an event or you manage a venue and you want to protect or restrict what sort of photography can be done and what can be done with the photographs. Excellent! There are a lot of reasons for this -- some better than others:
- Safety -- too many photographers in general or photographers in the wrong place can be dangerous, or at least annoying.
- Flash photography -- can be very irritating.
- Intellectual Property -- you want to protect your brand and are afraid that people taking photos will diminish it, or you're afraid someone will see a photo of whatever your venue is hosting and not go to it instead. This is stupid, but ok! I respect your dumb concern.
As an amateur/hobbyist photographer and frequent event attendee, I can give a few pointers what not to do in order to annoy people attending your thing:
"No professional cameras"
This makes no sense -- people are professionals (sometimes), not cameras.
"No cameras with detachable lenses", "No big cameras/SLRs", etc.
This is a relic of a bygone era -- a weird and nonsensical attempt to discriminate professionals from amateurs based on their camera. Even many consumer-grade cameras have removable lenses, and many professionals use cameras with fixed lenses. If I glue the lens onto my camera is it suddenly ok? High-quality cameras are ubiquitous these days -- trying to prohibit them entirely is a losing battle.
What your actual policy looks like of course will depend on your concerns (see above), but please stop using gear as an arbitrary substitute for prohibiting what you actually want to prohibit. If you don't want flash photography, prohibit flash photography. If you want to own all the photos taken, make everyone sign (or post?) a waiver of rights to any photos taken. If you don't want photography, ban cameras (good luck with that). Thanks in advance!