Canon EOS R3 Advanced User's Manual page 202

Slow Synchro
You can set the flash-sync speed for flash photography in [
maximum flash synchronization speed varies depending on the [
It is 1/180 sec. when set to [Electronic], 1/250 sec. for [Elec. 1st-curtain], and 1/200 sec.
for [Mechanical].
1/180-30sec. auto (
The shutter speed is set automatically in the following range to suit the brightness. High-
speed sync is also possible.
1/180-1/60sec. auto (
Prevents a slow shutter speed from being set automatically in low-light conditions. It is
effective for preventing subject blur and camera shake. Light from the flash provides
standard exposure for subjects, but note that backgrounds may be dark.
1/180 sec. (fixed) (
The shutter speed is fixed as follows, which is more effective in preventing subject blur
and camera shake than with [1/180-1/60sec. auto]
Note that under low light, backgrounds will be darker than with [1/180-1/60sec. auto]
* 1: When set to [Electronic].
* 2: [1/250-30sec. auto] (
[Mechanical].
*1*2
)
[ : Shutter mode] Setting
Mechanical
Elec. 1st-curtain
Electronic
*1*3
)
*1*4
)
[ : Shutter mode] Setting
Mechanical
Elec. 1st-curtain
Electronic
) when set to [Elec. 1st-curtain] or [1/200-30sec. auto] (
] or [ ] mode. Note that the
*1*3
.
202
: Shutter mode] setting.
Shutter Speed
1/200–30 sec.
1/250–30 sec.
1/180–30 sec.
Shutter Speed
1/200 sec.
1/250 sec.
1/180 sec.
) for
*1*3
.