Filter
Top Products
116
When 1/300 TTL High-Speed Sync is selected in TTL Auto
Flash mode, the guide number of the attached Speedlight
(except for a Speedlight for F3) is limited to the values shown in
the table below. Therefore, maximum flash shooting distance
cannot be calculated from each Speedlight’s flash shooting
distance scale or flash shooting distance range table provided.
ISO 100, m/ft., 20°C/68°F
Zoom-head
18mm 20mm 24mm 28mm 35mm 50mm 70mm 85mm
position
Guide number
8/26 8/26 11/36 12/39 14/46 16/53 18/59 19/62
(m/ft.)
To obtain maximum flash shooting distance in 1/300 TTL High-
Speed Sync:
Guide number
Flash-to-subject distance = ———————
f/stop
Example: Speedlight attached—SB-26, film sensitivity—ISO
100, zoom-head position—35mm, aperture—f/5.6
14 46
—— = 2.5m or —— = 8.2 ft.
5.6 5.6
Therefore, the maximum flash shooting distance of the example
is 2.5m or 8.2 ft.
•The minimum flash shooting distance can be obtained from
the Speedlight’s flash shooting distance scale or flash shoot-
ing distance range table provided.
•For film sensitivity other than ISO 100, multiply the following
coefficient to the guide number provided.
ISO number 25 50 200 400 800
Coefficient 0.5 0.71 1.4 2.0 2.8
•To select 1/300 TTL High-Speed Sync, set the camera’s
exposure mode to Shutter-Priority Auto or Manual, then set
the TTL flash sync speed to 3oo with the Custom Setting #20
(page 90). Other settings are the same as the Automatic
Balanced Fill-Flash (page 118).
•In 1/300 TTL High-Speed Sync, under-exposure warning may
not appear on the Speedlight when flash has fired at maxi-
mum output. Confirm exposure with the ready-light in the
viewfinder.
•Since the 1/300 TTL High-Speed Sync is an unique setting,
warning indications after flash is fired do not appear. Make
sure to confirm the flash shooting distance range.
Flash shooting distance range in 1/300 TTL High-Speed Sync
P400 (E) 02.12.27 6:42 PM Page 116