Canon EOS 5DS Instruction Manual page 235

Minimizing Blurred Photos
Use a sturdy tripod suited for the camera weight. Mount the camera
securely on the tripod.
Using a remote switch or a remote controller is recommended
(p.237).
In addition to mirror lockup, Silent LV shooting (p.266) and Silent
single shooting (p.142) are also effective.
When using mirror lockup, setting [Shoot * sec. after press] is
recommended. Selecting a longer time, such as [Shoot 2 sec. after
press], will increase time before the shot, reducing mirror shock.
Do not point the camera toward an intense light source, such as the sun
or an intense artificial light source. Doing so may damage the image
sensor or the camera's internal components.
In very bright light, such as at the beach or a ski slope on a sunny day,
take the picture promptly after mirror lockup is stabilized.
When [Press V twice to shoot] is set, single shooting will take effect
even if the drive mode is set to continuous shooting.
If [z4: Interval timer] or [z4: Bulb timer] is set to [Enable], you
cannot select [Press V twice to shoot].
If you use [Shoot *sec. after press] for Multi Shot Noise Reduction
shooting or HDR shooting, the [Shoot *sec. after press] setting will be
applied only to the first shot. (Continuous shooting will apply for the
second and subsequent shots.)
During mirror lockup, shooting function settings and menu are disabled.
When [Shoot * sec. after press] is set, you can also use the self-timer or
bulb timer with mirror lockup.
If 30 sec. elapse after the mirror has locked up, it will go back down
automatically. Pressing the shutter button completely locks up the mirror
again.
For mirror lockup, using a tripod and Remote Switch RS-80N3 (sold
separately) or Timer Remote Controller TC-80N3 (sold separately) is
recommended (p.237).
You can also use a remote controller (sold separately, p.237) with mirror
lockup. Setting the remote controller to a 2-sec. delay is recommended.
2 Mirror LockupN
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