The full fisheye frame shows everything above the horizon, including a lamp-illuminated landscape around the edges, and the zenith of the sky directly overhead.
全帧鱼眼镜头拍到了地平线上所有东西，包括边缘一圈被灯光照亮的地景，正在脑袋上方的天顶。
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Full cutoff means that no light rays from the lamp go above the horizon and that at least 90 percent of the light is blocked from going sideways.