Canon EOS Rebel T6i EF-S 18-55mm IS STM Lens Kit Instruction Manual - Page 164

Mirror Lockup to Reduce Camera ShakeK  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.  If you use the self-timer and bulb exposure in combination with a mirror lockup, keep pressing the shutter button completely (self-timer delay time + bulb exposure time). If you let go of the shutter button during the self-timer countdown, there will be a shutter-release sound, but no picture will be taken.  During mirror lockup, shooting function settings and menu operations, etc. are disabled.  If you use flash, the red-eye reduction lamp will not light up (p.167).  Even if you set the drive mode to , , or , the camera will still shoot in single shooting mode.  When [z3: High ISO speed NR] is set to [Multi Shot Noise Reduction], four continuous shots will be taken for the single picture regardless of the [9: Mirror lockup] setting.  If 30 sec. elapse after the mirror is locked up, it will go back down automatically. Pressing the shutter button completely again locks up the mirror again. 164