If you want to claim you need to firstly ring and check its covered (ie do you have personal possessions cover) and then get an estimate for repair. That is what you are initially covered for - you usually only get replacement if the cost of repair is greater than replacement with an equivalent model.
If you do opt for replacement but don't want the equivalent model or if repair cost is so high that you feel it would be better to put it to a new camera, you may be able to negotiate a cash settlement. If this is for replacement this will be less whatever discount the insurance company would get if they were replacing it, and of course less your policy excess.
If its a small amount then your excess may wipe most of it out and you end up with a claim on your policy, be aware that several small claims may prompt your insurer to put your excess up.
(This is from memory, I was a domestic property claims handler for a year or so between college courses, but that was a good few years ago and things may have changed.)