Here is my short list:
- Exposures tend to be much more accurate because you can see the image you will be creating before pressing the shutter button. This reduces or eliminates the need for chimping.
- You can use the EVF as a heads up display with virtual horizon or histogram.
- You can program a Fn button to allow zooming through the viewfinder - like electronic binoculars to take a photo. This allows me to look for precise timing such as when the bird's head is turning toward the camera, when there is a catchlight in the eye, etc. I only press the shutter when position is right.
- DX cropping is shown full size in the EVF. With an optical viewfinder, a DX camera magnifies the image to fill the viewfinder, but a DX crop is much smaller in an FX viewfinder. AF boxes are proportionately larger with DX. This makes DX a viable option for some subjects even with an FX mirrorless.
- You can playback images or adjust menu settings without your eye ever leaving the EVF. It's easier to see in bright light, and is faster.
- The EVF with focus peaking can show and highlight the area that is in focus. This makes manual focus much easier. Zooming can also help. I manually adjust focus much more often with my Z cameras because of the EVF.
- If you wear reading glasses, you no longer need them to closely examine focus, to check playback, or to make menu changes. All that and more is done through the EVF.
- The EVF is easier to see than the LCD in bright sunny conditions.
- The EVF is brighter than an OVF making it easier to see a subject in moderately low light - like indoors, at dusk or for heavy, dark cloudy conditions, etc.
- For astrophotography, chimping through the EVF means your LCD is not active and causing stray light to affect other photographers.
The drawbacks:
- There is a slight lag ( about 20ms) between what you see and what is actually occurring. It's about 35-50% of the lag on a new iPhone - much less lag - but still a lag compared to real time.
- There can be a short blackout between frames at high frame rates - kind of a mild strobe effect. This makes it harder to photograph fast erratic subjects like swallows.
- Timeouts cause the EVF and the camera to power down. You need to touch the shutter or AF-On button to wake the camera as you are moving it to your eye or moving your eye to a camera on a tripod. It's a change in technique but resolves the problem.
- Extremely dim light ( such as 3 stops darker than just after sunset - like the end of blue hour) cause the EVF to be grainy and show a lot of noise. Essentially you are using a very high ISO for immediate viewing through the EVF in very low light. You lose detail and pick up a lot of grain and noise.
- The EVF can be bright for astrophotography and needs to be reduced to prevent impacting your night vision.
- The EVF does not remain active when you have a long wait for action. Think watch a burrow and waiting for a subject to emerge.
- There is some impact of the EVF on battery life.
Whats the fn button setting that allows zooming? I need like 3 more function buttons
