We’ve posted about what shutter speed is, from a photographic standpoint, and shown the basics of how shutters works before. But this video from photographer Chris Marquardt takes things just that bit further. He literally pulls a shutter mechanism out of a Nikon D500 to show us the nitty gritty.
We all know the basic principles of how a shutter works. The front curtain opens, exposes the scene, then the rear curtain closes and our shot is complete. But the mechanism by which it all happens and the technology that allows it to work is quite fascinating.
I’ve actually been waiting for one of my older DSLRs to die so I can take it apart and see how some of its inner workings come together. But none of them seem to have done so yet. Now, I don’t need to (although I probably still will). The video illustrates shows how each of the two curtains essentially hinge on spring loaded levers.
When you hit the shutter, the shutter cocks, then the camera’s mirror flips up. Cocking the shutter pulls the front curtain in front of the sensor, while moving the rear curtain up out of the way. Electromagnets hold each of the curtains in place until the camera is actually ready to release them. Then the springs do the rest.
At the start of your shot, the magnet on the front curtain is released, opening it, and exposing your sensor to the light. At the end of the shot, the other magnet is released, covering your sensor with the rear curtain and ending the exposure. Then your mirror drops back down into place. This explains why longer exposures can cause your battery to drain so much more quickly. It’s using juice to hold that rear curtain open.
So, there’s more to potentially fail and kill a shutter mechanism than just the blades of the curtains getting bent. It’s no wonder that so many people are hoping for more cameras to come out with fully electronic global shutter sensors.