An apparatus having an optical reader system and method for label-independent detection having improved spatial resolution of the reader, as defined herein. The system includes an optical configuration for interrogating a sensor on a microplate at an incident angle (θ1) of greater than 45°, and recording the image received from the contacted sensor with the image recorder, the image recorder being oriented with respect to the reflected beam at a reflected angle (θ2) of greater than about 5°, as further defined herein.