The viewfinder is probably the most undervalued component of our cameras. It is the primary interface of the camera, yet most of us put up with a shrunken and dim viewfinder. The rest of the buttons and adjustments are secondary.
Recently, I was reading up a little on “bright” viewfinders to try to figure out what that was all about. I initially thought it had something to do with the percentage of coverage or the viewpoint, which spec sheets (sometimes) state, but I found out it does not. Once I figured things out a little, I decided to go and do some brightness tests on my own with some of the full-frame digital cameras out there (5D, a900, D700, 5DmII). Here is what I found.