There's a little 'key' icon in the camera controls, easy to overlook. It's on by default and will be white. Click it off and it will become a reddish color. Your camera settings will not affect any keyframes/poses you have done with your figures/props. Go to the animation pallet. From the list of items (figures, props, cameras and lights) pick your camera. Then click and drag to highlight the frames that you want to change interpolation on. You'll notice that Poser gives you four interpolation methods. I like to use "Linear Section" for most camera stuff, but I'm no expert. You may want to use "Constant Section" to make an abrupt camera move, there's a name for it that excapes me. Generally speaking "Spline section" is good for organic movement, linear for mechanical movement. There are plenty of exceptions, though. It's not a hard and fast rule.