There’s nothing like the sound of a professional camera shutter. It’s become so synonymous with photography that digital cameras and phone cameras often have a fake sound effect to make the photography experience more authentic.

But have you ever wondered about the process behind that magical sound effect?

When it comes to a DSLR camera shutter there are 3 basic mechanisms: the mirror box, the bottom door, and the top door. When you look through a DSLR viewfinder you are essentially looking through a series of mirrors that get their light directly from the lens. When you click the shutter button that system of mirrors flips upwards to allow light to pass to the sensor. This is why the viewfinder goes black for a short amount of time when taking photos.

Once the mirror is flipped upwards a small door will move from top to bottom exposing the sensor beneath. After that another door will fall down, covering up the entire sensor. This process can vary in time depending on the length of your shutter speed. Sometimes a shutter speed can be so fast that your camera sensor won’t be entirely exposed at any one time.

After the second door closes your mirror will fall back into place. The doors will then reset to their original positions underneath. This entire process from mirror up to mirror down is known as actuation. A typical DSLR can withstand over 100,000 actuations in its lifetime.

Credit: https://www.premiumbeat.com/blog/how-camera-shutters-work/