Interesting. I'll have to try that. The "fovea centralis" has a higher concentration of rods. So when you look "at" something (i.e. move your eyes so that the image is striking your fovea) then the image is received by a lower concentration of cones. Cones require more space because they need more light collecting ability to capture a smaller fraction of the spectrum. It's the same reason why colo(u)r film produces more grainy images than B&W film. Presumably, the part of your retina that is responsible for peripheral vision can accommodate a higher concentration of cones because of the lower concentration of rods. This also relates to the needs of hunters/gatherers. When hunting, predators use their peripheral vision mostly to spot prey initially then they use their fovea to stalk. Gatherers use their peripheral vision to find nuts and fruits and when they find them, they use their peripheral vision again to judge their suitability for consumption using color. But they also use their central vision to inspect closely for flaws.
The tradeoffs in biology are fascinating. It always brings me back in awe of the archosaur eye (e.g. birds and other dinosaurs). They see more clearly than mammals across the whole surface of the eye because the capillary blood supply to the retina in mammals is on top of the sensors. So the light has to pass through this tissue and is distorted some before being received. In birds, the blood supply comes from behind the retina and does not interfere with vision. The embyological implications are intriguing. This is why eagles are said to have 8~10X more visual acuity than humans. Also, birds have more types of color receptors than mammals. While we perceive only three "primary colo(u)rs" birds have at least four seeing ultraviolet to which we are totally blind. Next time you think about what it would be like to be stalked by a 10 meter Allosaur or Torvosaurus, just contemplate all of your disadvantages and you will understand what mammals had to deal with during the Mesozoic. People once thought Dinosaurs to be sluggish stupid reptiles that went extinct because of their inferiority. Hahh! They couldn't have been more wrong. The way we think about dinosaurs began to change after Bob Bakker wrote his book "The Dinosaur Heresies". I am going to the Houston Museum of Natural Science this evening to hear him speak. My wife and I talked with him at breakfast twice because we were staying at the same hotel for the SVP meetings in Austin.
Sorry, I got into 3D and TG2 because of dinosaurs (among other extinct animals). My mind is never very far from them.