The quality of a teleoperation system depends on a combination of device characteristics and human perception. This paper presents a study on the relationship between human size discrimination capabilities and teleoperator stiffness for a finger grip grasp task. The teleoperator stiffness was varied in a wide range, and for each setting the human size discrimination capabilities was measured. The teleoperator grasp performance was also compared with two reference conditions: bare hands and fingers in brackets. It was found that the teleoperator stiffness has no measurable influence on operator performance. It was also found that humans surprisingly perform equally well using the teleoperator as with bare hands