Electronic Viewfinder
A small high-resolution display inside the eyepiece showing a live feed from the sensor.
In depth
An electronic finder can show exposure, white balance, focus peaking, a live histogram and the final picture profile before capture, which turns exposure from prediction into observation. Its limits are lag, refresh rate and dynamic range: a very high-contrast scene can look worse in the finder than it will in the file, and fast panning can smear at lower refresh settings.
Examples in practice
Setting a silhouette becomes trivial when the finder already shows the subject rendered black against a bright sky.