ISO 19012-1:2013规定了显微镜物镜上标记“平面图”的使用，并定义了平面物体表面主图像锐利区域的直径。ISO 19012-1:2013适用于制造商规定的使用物镜、管镜和目镜组合的视觉观察。 该标记与ISO 8578一致。

ISO 19012-1:2013 specifies the use of the marking "Plan" on microscope objectives, and defines the diameter of the sharp region of the primary image of a flat object surface. ISO 19012-1:2013 applies to visual observation using the combination of objective lens, tube lens and eyepiece, as specified by the manufacturer. This marking is consistent with ISO 8578.