In order to realize high resolution angular measurement, a subdivision method based on the photographic sensor is proposed. A more adaptable high-resolution subdivision algorithm is proposed to eliminate the subdivision error caused by the irregular distance between the photographic sensor and the grating center during installation and adjustment of the encoder. The mathematical model of the proposed subdivision algorithm is established, and the error of the method is analyzed. Based on practical working conditions, an error model which takes many aspects into consideration is built and the effect of various elements on the subdivision algorithm is analyzed. According to the error analysis results, how to reduce the subdivision error of photographic encoders is recommended. Experimental results show that the subdivision error can be ignored when the line number of circular grating is more than or equal to 128. The results can provide theoretical foundation for develop the miniature photographic encoder.