Which contains more information, an image that is in focus or one that is out of focus? I did an experiment to find out.
To do this I shot 2 sets of three images each. The first set represented a typical image (flowers) and the second was a low-contrast image (pavement). I shot in focus, somewhat out of focus and a very out of focus image for each set. The camera image quality was set to JPEG NORMAL (I wanted to compress the images). I used the compressed image filesize as a way to get a measure of the amount of information contained in an image. The larger the filesize the more information contained in the image.
In both sets the in focus image contained the most information and there was a significant drop in information between the in foucs and somewhat out of focus images (see images above). The was also a drop in the amount of information between the somewhat out of focus and the very out of focus images but not to the degree of the in focus and somewhat out of focus images. It appears that even slightly out of focus images may experience significant information loss.
