In the case of professional photographers, your options (and liabilities) are greater. You can still put your equipment on a rider, but it will be specifically for a professional photographer. The cost is, as you may suspect, more expensive than for just a household. It will also contain coverage for things like liability, in case someone trips over your light stand and sues. Many clients, typically, will require a multi-million dollar umbrella policy before you can even step foot on their premises with a camera. Better be safe than sorry.