Three.js First Person Controls

I'm playing around with Three.js and WebGL and can't quite get the controls the way I want. I chose to try to "roll my own" controls since Three.js's FirstPersonControls do not use pointer lock.

Anyway, I took most of my code from the built-in FirstPersonControls, converted it to use pointer lock (movementX instead of pageX - offset), but I am having trouble smoothing the look motion.

Here is my onMouseMove (using originalEvent since it is a jquery event):

onMouseMove: function(e) {
    if(!document.pointerLockElement) return;

    var moveX = e.originalEvent.movementX       ||
                    e.originalEvent.mozMovementX    ||
                    e.originalEvent.webkitMovementX ||
                    0,
        moveY = e.originalEvent.movementY       ||
                    e.originalEvent.mozMovementY    ||
                    e.originalEvent.webkitMovementY ||
                    0;

    //Update the mouse movement for coming frames
    this.mouseMovementX = moveX;
    this.mouseMovementY = moveY;
}

And my Controls.update() (called on each animation frame, with the THREE.Clock delta):

update: function(delta) {            
    if(this.freeze) {
        return;
    }

    //movement, works fine
    if(this.moveForward) this.camera.translateZ(-(actualMoveSpeed + this.autoSpeedFactor));
    if(this.moveBackward) this.camera.translateZ(actualMoveSpeed);

    if(this.moveLeft) this.camera.translateX(-actualMoveSpeed);
    if(this.moveRight) this.camera.translateX(actualMoveSpeed);

    /////////
    //ISSUES ARE WITH THIS CODE:
    /////////
    //look movement, really jumpy
    this.lon += this.mouseMovementX;
    this.lat -= this.mouseMovementY;

    this.lat = Math.max(-85, Math.min(85, this.lat));
    this.phi = (90 - this.lat) * Math.PI / 180;
    this.theta = this.lon * Math.PI / 180;

    this.target.x = this.