Estimate a suitable panning shutter speed from subject speed, direction and focal length to keep the subject sharp with directional blur.
根据目标模糊效果可上下调整。
| Item | Formula / Rule | Source / Standard |
|---|---|---|
| Safe shutter | Handheld safety shutter is about 1 ÷ equivalent focal length in seconds | ISO 12231:2012 Photography — Vocabulary |
| Motion smear | Background smear equals angular rate × shutter time × focal length and must stay within tolerance | ISO 12231:2012 Photography — Vocabulary |
| Hit rate | Shooting 10 to 20 frames per pass usually lands 20% to 40% of them | ISO 2720:1974 General-purpose photographic exposure meters |