I'm wondering how the mirror in a DSLR or SLR camera is flipped up (and back down again) when a photo is taken.

Is this mirror typically actuated by a motor, magnet, spring and gravity, or something else? If there are any specific examples, I'd also love to see how this mechanism actually looks.

  • \$\begingroup\$ Have you searched online? I know I've seen this before, someone even filmed it working with an ultra-high-speed camera. \$\endgroup\$
    – Itai
    Commented May 26, 2015 at 20:36
  • \$\begingroup\$ I've seen a few videos, although it's a bit difficult to see what's going on, or how any of the actuation is happening. \$\endgroup\$
    – Clyde W
    Commented May 26, 2015 at 21:09
  • 1
    \$\begingroup\$ This article on the Nikon D4 mirror box patent diagrams may be interesting. I assume the patent describes how it works photographybay.com/2011/09/29/nikon-pro-dslr-d4-patent-diagrams \$\endgroup\$
    – Aaron
    Commented May 26, 2015 at 22:31

1 Answer 1


Today, most DSLR mirrors are operated by a dedicated motor. Return springs are used to move the mirror back into position. Some DSLR's have two mirror motors. One to raise and one for return. Here is a video that shows how the Canon EOS 7D Mark II operates: https://www.youtube.com/watch?v=kLU5oygrkpw

7D Mk II mirror

  • \$\begingroup\$ Nice! Thanks; The precision of such a device is impressive. \$\endgroup\$
    – Max
    Commented May 27, 2015 at 15:18
  • \$\begingroup\$ S/Hear/Here/ for some reason I can't fix it myself. \$\endgroup\$
    – JDługosz
    Commented May 27, 2015 at 15:20
  • \$\begingroup\$ The 7D Mark II is not typical, as it was one of the first motor driven return mirrors incorporated into anything other than a professional "flagship" model. \$\endgroup\$
    – Michael C
    Commented Apr 6, 2016 at 13:46

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