EVF stands for Electronic View Finder. EVFs are a relatively new innovation in digital camera technology which was generally discouraged by most photographers when they were first announced, and now have become so good that many or most photographers prefer working with a camera with an EVF.
On a traditional DSLR camera, the image in the lens comes through the camera and is bounced up into the viewfinder by a mirror and a prism. So what you see in the viewfinder is an actual, optical view of what the lens is capturing. There are no electronics in this process–much like if you were looking through binoculars.
An EVF, however, is used on a mirrorless camera (click to see my recommendations of the top 10 mirrorless cameras under $1,000). On a mirrorless camera with an EVF, the light from the lens goes straight to the imaging sensor which records the data and shows a preview of what the sensor captures on a tiny little TV screen viewfinder. It's basically just a tiny version of the LCD screen on your camera when shooting in live view mode.
What are the Benefits of a Camera with an EVF?
I didn't like the EVF cameras when they were first released. They were laggy, which means the preview of what you see in the screen is a split second behind what is happening in real life. This makes action shooting difficult. They were also small and didn't have good resolution.
- Histogram display. Since the image you see in the viewfinder is recorded on the imaging sensor, the camera can use that data to show a histogram of the brightness levels in the photo. This is very important to help properly expose a photo in a difficult lighting situation.
- Live display of how the photo will be rendered. One problem with cameras is that they don't have the dynamic range to show all of the brightest parts in the photo and the darkest shadow detail. Since you can see right in the EVF how the brights and darks are captured, you can plan your camera settings accordingly.
- Focus distance display. Handy to have when calculating the proper aperture for a landscape, but not that big of a deal.
- The image is much brighter in dim environments. Since you have the benefit of the ISO, you can see in much dimmer environments where a DSLR couldn't see anything.
- Focus peeking
- Focus assist zoom
- After you take a photo, you see the preview right in the viewfinder without needing to take your face off the viewfinder and look at the LCD, and then go back to the viewfinder for another shot.
Drawbacks of an EVF
- Drains battery much more quickly. Since you're powering a monitor, albeit a tiny one, the power has a tendency to go down more quickly. Easy solution–buy more batteries!
- Brightness – Looking into a little monitor can sometimes take a second for your eyes to adjust to if it's bright outside.
There are benefits and drawbacks to using an EVF on your camera, but personally, I would never want to go back to a traditional mirror setup. I LOVE the EVF of my Fuji XT1 (read here about why I switched from Nikon to Fuji).
I love the extra amount of data that the EVF can show me that the old mirror setup cannot. While it can take a little time to get adjusted to having a little monitor preview if you're used to the mirror, I'd really encourage everyone to at least give it a try. Once you get used to it, I think you'll be hooked as well.