精密金属刻度测量仪器正面特写

竖幅产品摄影，精密古董金属测量仪器正面平视特写，主体居中充满画面。仪器由银灰色金属刻度环、黄铜色中央碗状圆盘、深灰色圆形玻璃片、两侧竖直齿轮齿条、细密刻线与数字刻度组成；上方小圆盘带放射状刻痕，下方大型弧形刻度尺清晰可见。黑色底衬背景，画面外缘白色，棚拍均匀照明，金属冷灰反光与暖黄铜色形成对比，构图对称，细节清晰，画幅比例3:5。

Vertical product photography, front-facing close-up of an antique precision metal measuring instrument centered and filling the frame. It features silver-gray metal circular scales, a brass-colored central bowl-shaped disc, a dark gray circular glass insert, vertical toothed racks on both sides, fine engraved graduations and numerals; a smaller upper dial with radial markings and a large lower arc scale. Black backdrop with white outer margins, even studio lighting, cool metallic reflections contrasted with warm brass tones, symmetrical composition, sharp details, portrait 3:5 aspect ratio.