Canon EOS Rebel SL1 18-55mm IS STM Kit Instruction Manual page 191

When you press the shutter button halfway to autofocus during movie
shooting, the following phenomena may occur.
• Focus may become far off momentarily.
• The brightness of the recorded movie may be different from that of the
actual scene.
• The recorded movie may be momentarily still.
• The movie may record the lens operation noise.
• You cannot shoot still photos when focus is not achieved, such as when
the subject is moving.
k Shooting Movies
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