This paper is about the precision performance evaluation of an XY-theta platform, with a patented kinematic design. Indeed, this platform is held by a serial redundant robot arm actuated with four revolute joints. The platform offers a wide 300 × 300 mm workspace, whereas the whole mechanism is extremely compact. Any workpiece on the platform can be positioned under a vertical axis to be grasped or manufactured in a two-step approach: in a coarse positioning mode, the four revolute joints are controlled to position and orientate the workpiece with a position error of less than 10 μm; in a fine positioning mode, two revolute joints are mechanically blocked while two others are controlled to reduce the final error to below 2 μm. The mechanism design and the choice of the blocked and moving joints are optimized to enhance the positioning performances in the two-step positioning method. In this paper, the platform positioning repeatability and its spatial resolution are characterized with the help of a camera. The advantage of this method is that it avoids any mechanical contact and can be implemented easily. Then, these results are compared to our previous precision performance evaluation obtained with the stationary cube method. Finally, the positioning repeatability is estimated at 6.5 μm in the coarse positioning mode and 1.4 μm in the fine positioning mode. Between the coarse and fine mode, the repeatability is thus improved by the factor of four, as predicted by the theory.