A good resolution for a backup camera is whatever you can see clearly. That answer is a bit cheeky, but there’s something to it. Typically, you’ll only be viewing what your backup camera captures through a small monitor; some made small enough to fit in a portion of a rearview mirror, so resolution isn't as important as when selecting a TV. The result is that resolution isn’t as important for backup cameras as it is for other cameras. In other words, you don’t need an ultra-high-definition camera just to look at the image through a 4-inch screen. Instead, prioritize a quality angle of view so you can obtain the most information possible.