Moving the camera on an ellipse

Hi, I’m trying to move my camera around the origin in a sphere like direction.
My first try now is that I described the ellipse of the sphere with the following formula

camX = camDis * sin(alpha * (PI/180)) * cos(beta * (PI/180));
camY = camDis * sin(alpha  * (PI/180)) * sin (beta  * (PI/180));
camZ = camDis * cos(alpha * (PI/180));

alpha and beta are getting increased or rather decreased by moving the mouse around. Up to now alpha gets raised if I move the mouse up and beta if I move the mouse to the right.
Unfortunately this is not giving me the effect I wished for.
I would like to have the rotation like it is in 3ds max or in blender. Does anyone know how to do this?