Advances in optics and image sensors for interchangeable-lens cameras have made choosing the right camera more complicated than just big vs. small.

Purchasing a new camera presents a wide array of choices in body style, optical range, display size, resolution and more. But until a few years ago, the first decision was a simple one: Did you want a compact camera with a single built-in lens, or did you want to pay a lot more money for a much larger camera that could work with multiple lenses...