The Panasonic Lumix DMC-G1 has made history as the first non-SLR digital camera to sport interchangeable lenses. And while it exceeds my expectations with respect to speed and photo quality, it lives down to them, unfortunately, with respect to the shooting experience, thanks to its use of an electronic viewfinder. (For the uninitiated, an EVF is a little LCD display used for eye-level shooting.) While EVFs aren't new--they're a staple on megazoom cameras and camcorders with eye-level viewfinders--I realized I'd never cohesively stated why I dislike them.
Some people have no problem with EVFs, and I daresay there may be people who even like them. They do have a couple advantages, such as the ability to preview exposure when implemented, which you can't do with an optical viewfinder (though some dSLRs are offering that capability in Live View mode).
But I find EVFs incredibly distracting when I'm shooting. For one thing, they never simply fix exposure; when you focus and recompose, or if the light simply changes, it has to gain up or down to compensate so that you can still view the scene. Even if you mentally adjust for that and know that what you see in the viewfinder doesn't reflect the real exposure, the constant change is incredibly annoying. The only time that can be useful is when you're shooting in extremely dark conditions where you probably couldn't make out the image in an optical viewfinder. But then there's so much noise in the EVF that it's hard to see anyway.
In addition, EVFs black out when you take a shot. That's not much of a problem with random single shots, but for any type of sequential shooting you can easily lose track of the subject. You might as well just close your eyes and pray.