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5.4 Information in the LC display
Canon EOS cameras transmit the ISO film speed, focal length (mm), f-stop
and exposure correction to the flash unit so that the flash unit automatically
adapts its settings accordingly. The maximum flash range is then calculated
from these values and the flash unit’s guide number. Flash mode, maximum
flash range, aperture and the zoom reflector position are all indicated by the
LC display of the flash unit.
If the flash unit operates without having received data from the camera (e.g. when
the camera is switched off), then only the selected flash mode, the reflector position
and „M.Zoom“ are indicated. Aperture and maximum flash range are only dis-
played if the camera transmits the corresponding data to the flash unit.
Some cameras suppress the maximum flash range indication on the
LC display in the event of high ISO values (e.g. ISO 6400) or flash
exposure corrections.
Various cameras (e.g. PowerShot G1) do not transfer any f-stops to
the flash unit. In such an event the LC display of the flash unit will not
indicate f-numbers or maximum flash ranges. This, however, is irrele-
vant for correct operation of the TTL or E-TTL flash mode.
5.4.1 Maximum flash range indication in TTL flash mode
The LC display of the flash unit indicates the maximum flash range. The indi-
cated value relates to a factor of 25% of light reflection by the subject, which
applies to most photographic situations. Pronounced deviations from this re-
flection factor, e.g. highly reflective or poorly reflecting objects, can influence
the maximum flash range of the flash unit.
Always observe the maximum flash range indicated by the LC display of the
flash unit. The subject should be within approx. 40% and 70% of the indi-
cated value. This gives the electronic circuit sufficient scope for compensa-
tion. To avoid overexposure, the minimum flash-to-subject distance should not
be less than 10% of the indicated value. Adaptation to the given photogra-
phic situation is possible by changing the aperture setting on the lens.
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Example:
The display indicates a distance of 6.2 m.
Ideally, the subject should be located within a distance range of approx.
2.5 m and 4.3 m.
5.4.2 Maximum flash range indication in the manual flash modes
M and MLo
The LC display of the flash unit indicates the distance to be maintained for
correct exposure of the subject. Adaptation to the given photographic situa-
tion is achieved by changing the aperture setting on the lens and selecting
either „M“ for full light output or „MLo“ for partial light output (see 4.4).
5.4.3 Exceeding the display range
The flash unit can indicate a maximum range of 199 m or 199 ft. This dis-
play range can be exceeded in the event of high ISO values (e.g. ISO 6400)
and large aperture openings. An arrow or triangle after the distance value
indicates that the display range has been exceeded.
5.4.4 Blanking out the maximum flash range display
The LC display of the flash unit does not indicate any distances when the re-
flector head is swivelled up or down out of its normal position!
5.4.5 Meter-Feet changeover (m - ft)
The maximum flash range indicated by the LC display of the flash unit can be
either in meter (m) or feet (ft). To change between the two, proceed in the fol-
lowing manner:
• Turn off the flash unit by its main switch.
• Keep the „Select“ key combination depressed (= „Mode“ key + „Zoom“ key).
• Turn on the flash unit by its main switch.
• Release the „Select“ key combination (= „Mode“ key + „Zoom“ key).
• The flash range indication changes from m to ft or from ft to m.
