Methods of measuring RoM in knee

Hi, im just wondering if you have any recommendations for patient positioning when measuring knee flexion and extension.
On another note i am also wondering what you all find to be your most effective equipment for measuring joint angles, as the classic goniometre i have found to be a bit subjective. I was wondering if any of you have experimented with using a digital camera and then using pc software measuring the angle.
Thanks for reading and any suggestions welcome