Aperture The aperture ring functions the same as our iris, making the hole in the centre function like our pupil, regulating light traveling through, its angle and amount; large aperture (low f/stop numbers) is the same as a large pupil and vice-versa. Aperture size is inversely proportional to the size of the f/stop (aperture number), f/32 is very small and f1.4 is relatively large. The aperture is displayed on this diagram, including light, depth of field and "sweet spot" of the lens Larger aperture sizes (Smaller f/stop numbers) make a more obvious depth of field, making the background blurred due to larger amounts of light entering. Smaller aperture sizes (Larger f/stop numbers) make a lesser depth of field and allow more of the image in focus, better for landscape photography, less light that is cascading will enter, making more straight light beams and making a more "focused image".