Jerky keyboard input

Unity Engine
1

Right now I have a script with this:

void Update () {
        if (clickedOn)
        {
            // rotating object based on left arrow key
            if (Input.GetKeyDown (KeyCode.LeftArrow)) {
                this.transform.Rotate (0f, 0f, 5f);
            }
        }
}

But when I rotate it, I have to press the left arrow key once for each slight rotation, instead of being able to hold down the key and keep it smoothly rotating. Am I missing something?

2

try Input.GetKey