Canon EOS Rebel T5 18-55 IS II Kit - Manual (Page 288)

Troubleshooting Guide
288
Under [53: Custom Functions (C.Fn)], if [6: Highlight tone priority]
is set to [1: Enable], ISO 100 cannot be set. If [0: Disable] is set, ISO
100 can be set (p.261). This also applies to movie shooting (p.173).
Under [53: Custom Functions (C.Fn)], if [6: Highlight tone priority]
is set to [1: Enable], the [H] ISO speed (equivalent to ISO 12800)
cannot be selected even when [2: ISO expansion] is set to [1: On]. If
[6: Highlight tone priority] is set to [0: Disable], [H] can be set
(p.261).
Under [53: Custom Functions (C.Fn)], if [6: Highlight tone priority]
is set to [1: Enable], Auto Lighting Optimizer cannot be set. If [0:
Disable] is set, the Auto Lighting Optimizer can be set (p.261).
Set [z2: Auto Lighting Optimizer] to [Disable]. When [Standard],
[Low] or [High] is set, even if you set a decreased exposure
compensation or flash exposure compensation, the image may come
out bright (p.119).
If you shoot at night when the background is dark, the shutter speed
becomes slow automatically (slow-sync shooting) so that both the
subject and background are properly exposed. To prevent a slow
shutter speed, under [53: Custom Functions (C.Fn)], set [3: Flash
sync. speed in Av mode] to [1: 1/200-1/60 sec. auto] or [2: 1/200
sec. (fixed)] (p.259).
ISO 100 cannot be set.
ISO speed [H] (equivalent to ISO 12800) cannot be set.
The Auto Lighting Optimizer cannot be set.
Even though I set a decreased exposure compensation,
the image comes out bright.
When I use the <f> mode with flash, the shutter
speed becomes slow.
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