Usually one can first meter using a larger aperture (so that the metered exposure time is under 30 seconds), then stop down as necessary and multiply the exposure time accordingly.

通常，你可以用大点的光圈测光(这样，测量的曝光时间就在30秒以内)，随后缩小光圈，相应地增加曝光时间。

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Usually one can first meter using a larger aperture (so that the metered exposure time is under 30 seconds), then stop down as necessary and multiply the exposure time accordingly.

通常，你可以用大点的光圈测光(这样，测量的曝光时间就在30秒以内)，随后缩小光圈，相应地增加曝光时间。

youdao