Lumix LX5 sharpest aperture
Maybe I was completely unscientific here, but I just did like this: Took a photo from a tripod onto a wall and some books and different things lying 2.5 meters away. The tiny titles on the binding of the books were readable on the 5.0 and 5.6 shot, but much harder to read on the 4.0 and 2.0 shots. All shots were done in raw with no correction applied. With correction applied of course the results were the same.