My Canon 580EX II has a distance scale running from 0.5m to 18m.

When the flash is in manual mode, a single segment of the distance scale illuminates to indicate the maximum effective range for my current aperture and ISO settings.

In E-TTL II mode, the scale illuminates a number of segments. For example, if I set my aperture to f5.6 and ISO to 400, 7 segments illuminate between 1m and 9m. What does this mean?


This shows you the optimum range of distances you can use those settings with. In your example, beyond 9m and the camera settings mean you won't be able to illuminate the subject properly; and closer than 1m and the subject will be overexposed even on the flash's minimum setting.

In manual mode, you've already determined the flash power, so the effective range is reduced to just the single bar.

  • No probs - have fun! – NickM May 27 '11 at 14:14
  • Will the 580 fig. out the distance as with the sb-900{Nikon}? Thanks, William – user19409 Apr 17 '13 at 1:44
  • I can't speak for the Nikon, but as has been said, the 580 will show you the specific distance in manual mode, and the range of available distances with the aperture/ISO selected in E-TTL mode. – NickM Apr 17 '13 at 9:47

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