You CAN grab the cameras and move them around. All you need is to enable them in the hierachy-editor, then they're "grabbable" If the scene updates slowly it can help to see the scene in wireframe or one of the other untextured modes, it takes up far less ressources on large scenes. Also the Fast tracking option can help.

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.