超写实PBR三维渲染，中世纪骑士盾正面正对镜头居中放置，盾体为尖底水滴形钢制，深暗灰铁原色，表面带有锤击凹凸痕迹、多处划痕、红褐色锈斑与零星蓝绿色铜锈痕迹，边缘沿轮廓均匀排布一圈圆形银灰色金属铆钉，盾面中央铸有凸起的向前迈步的狮形金属浮雕，前爪呈抬起姿态，狮身被盾牌正中央的圆形凸起金属饰件部分遮挡，该饰件为做旧银灰色金属材质，表面带有类似骷髅面部的凹孔纹路，饰件边缘均匀分布一圈小型圆形金属铆钉，盾体后侧边缘露出棕褐色皮革绑带的局部轮廓，背景为纯深暗灰色影棚背景，无其他多余物体，侧前方柔光打光，突出金属表面的磨损肌理与浮雕的立体阴影，底部带有轻微的自然投影，正方形画幅，高细节写实质感。

Photorealistic PBR 3D render, a medieval knight's shield facing directly toward the camera in the center of the frame. The shield has a pointed-bottom, teardrop-shaped steel form in dark gray iron tone, with hammered concave-convex textures, multiple scratches, reddish-brown rust spots, and scattered blue-green verdigris marks across its surface. A circle of round silver-gray metal rivets is evenly arranged along the edge of the shield's border. A raised, three-dimensional sculpted rampant lion relief sits at the center of the shield face, with front paws raised in a forward-stepping pose; the lion's body is partially obscured by a round raised metal ornament at the exact center of the shield. This ornament is made of distressed silver-gray metal, with concave hole patterns resembling a skeletal skull face on its surface, and a ring of small round metal rivets evenly distributed around its outer edge. Local segments of tan leather straps peeking out from the rear edge of the shield body. The background is a plain dark gray studio backdrop with no other objects present. Soft side-front lighting highlights the worn texture of the metal surface and the dimensional shadows of the relief, with a faint natural shadow cast under the shield. Square aspect ratio, high-detail photorealistic texture.