A couple of things to keep in mind about Poser Key Frames: 1) they apply from the top of the list down, and unless you change modes will be set to replace instead of add. 2) As soon as you make a change to a parameter on that layer it will be in effect until the layer ends. What this means is that if you create a layer that goes from frame 30 to 120 (out of say 200 frames) and make a change to the X translate of the camera and this is the topmost layer to have a change to the X translate (you can layers above as long as they do not effect that parameter) then when you get to frames 30 to 120 the new parameter will kick in. 3) Large changes to the position of an element from layer to layer can cause the spline curve of the movement to swing to extreme values causing the jumping effect. This is especially true if you set the layers to add mode.

The best way to learn animation is to use simple objects such as cubes and play with the various options like layers and adding and replacing.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13