Which camera has the biggest and brightest viewfinder?

Which camera has the biggest and brightest viewfinder?

Added (1). Among present generation entry level DSLR's

For an entry-level DSLR, the winner is probably the Pentax K-500.

Unlike competitors from Canon and Nikon, it has a pentaprism (other manufacturers use penta-mirrors, which are cheaper) with 100% coverage. Throw in that it meters with MF lenses (Canon can't take them, and entry-level Nikons can't meter with them) and a body mounted anti-shake system (works with any lens fitted), and you wonder why people even bother with the other two.

The Sony A-58 does of course, have an electronic viewfinder with 100% coverage - but even the best electronic viewfinders have difficulty following a moving subject when compared to the optical systems of a true DSLR.

Higher end DSLR's like the Nikon D7100 usually have a bigger, brighter pentaprism than the penta-mirror in more economy models in the line like the D3300 or D5300.
Probably the best viewfinder in a one-step-up-from-the-bottom model is the Pentax K50.
The bottom-rung K500 has that, too, but I would skip the K500 because of its lack of user control of the autofocus sensor. Also, the K50 throws in the best weather sealing for its price.

Probably the best beginner model is a one-step-above-beginner model. Beginner models like the Canon T5, Nikon D3300, and Pentax K-500 often lack something that you will covet in the D5300, T5i, or K-50.

All of the big cameras have 100% coverage, pentaprism viewfinders. Canon 1Ds, Nikon D3x, Sony A900, Pentax 645Z.

Pentax, ever since the old days of film, always had bright and comfortable to look through viewfinders.