What is an electronic viewfinder?

On a DSLR camera, such as the Nikon D850, light enters through the lens and is bounced by a mirror and prism into the viewfinder, where you see a live view of what is coming into the camera, as if looking through a window, with no electronics involved.

In mirrorless cameras, light goes to the sensor directly and is then sent to a tiny screen in the electronic viewfinder or EVF. This means that what you see through the eyepiece is exactly the same as what you will see on the rear screen of the camera, with all the camera and image data displayed and access to the full camera menu system.

Using an EVF also means you can see what happens to your image when you change ISO and exposure before you take a shot, and you can see the shot itself after it has been taken without having to move your eye out of the viewfinder to look at the camera screen.

In Nikon Z cameras, the high-quality EVF has minimal lag, so what you see through the eyepiece is what is happening in front to the camera and is customisable, meaning you only see what you want to see. Use the ‘Apply settings to live view’ function and the EVF and screen will show the same brightness, contrast and colour. Turn that setting to ‘Off’ and they will both display something more like what you would see when using a DSLR.