If you have game, then why choose such a demeaning picture that makes the game look less than it does? Yes, the interior darkens when the race starts, and yes things look a bit better in Photo Mode but that's largely because only a set distance is being rendered, not the entire environment and eight cars, and even when eight cars are in frame (let's say you want to take a photo of something involving the other seven vehicles. An incident, perhaps) the same still applies - only a set distance is going to be rendered, and beyond that distance things aren't going to be as high of quality.
For comparison's sake, GT5's photo mode will take pictures at 18MP. You have any idea what resolution that is? Everything is going to look better in Photo Mode because there's less to render, therefore there's more to dedicate to the entire scene(s).