Lately I've been doing some tutorials for Zbrush and I've been encountering some major problems with the camera. I've been given some reference images and set them up in Zbrush, but I can't tell if I accidentally keep moving them or the camera moves in a way that mis-aligns my camera with the reference placement (Most likely the latter). I can't seem to constrain the camera to a certain viewpoint without moving it. The closest I can get is a SHIFT+Drag, but even that isn't consistent and doesn't necessarily keep the camera still or in the same position.
I can't seem to constrain my actions either. The tutorial called for the use of ZSpheres to make a base mesh for the body, but if I can SHIFT+Click my perspective to something akin to a side-view or front-view and move my Z-Spheres according to the reference image, I find that when I change my perspective, I see they were also moved in another axis and so now it doesn't align in my front view. Similar things happen when I adjust my model in the front view and switch to the side-view.
I've been fooling around in ZBrush for a bit, but I'm only now getting serious about learning it. Can someone please tell me how I can solve these navigation problems.