A high definition video signal can easily fill up a large screen with a vividly detailed moving image.
The Pixel to Pixel feature essentially displays an HD video signal at its full size, so only a small portion of the image will be visible on an field monitor’s small screen. Think of the Pixel to Pixel feature as a way to quickly zoom in and out of the image on screen, without the need for optics or a grainy “digital zoom” feature.
It’s useful to be able to see the fine details of a shot without adjusting the lens or downgrading the resolution. For example, say you need to check if your subject is in focus. You can engage the Pixel to Pixel feature, making a small portion of your subject fill up the screen. You will instantly see if the image looks as sharp as possible.
You can adjust the focus while zoomed in, and instantly exit the Pixel to Pixel mode to see the entire frame of the shot.