• The aperture of the lens works in a similar way to the iris of your eye.
• Just like the iris which expands in the dark and contracts in bright light, so does the aperture of the lens
• However, unlike your iris which automatically reacts to light all the time, the Aperture ring of your lens can be manually adjusted.
• Within most modern camera lenses, there is a diaphragm which the user of the camera can use to open and close and control how much light is being allowed in.
• This opening created by the diaphragm is referred to as the Aperture and these are given the F-numbers you refer to. Also known as f-stops because this is the aperture setting that limits how much light is let in and therefore, limits the brightness of the image as the pupil size is restricted.
• Most Lenses today use a standard ADJUSTABLE f-stop scale. I.E f/1.2. f/1.4, f/1.8, f/4, f/5.6, f/8, f/11, f/16/, f/22, f32. (Some lenses will have even a wider range)
• f/1.2 will be the largest opening and therefore letting in the most light and f/32 being the smallest and therefore letting in the least light.
• However, f/1.2 will have a shallow depth of field and as you close the aperture, the depth of field will increase. (f/8-f/16 is often a good choice for landscapes) Smaller apertures can result in refraction
• People prefer to purchase a lens with the biggest aperture possible as it makes the lens a more versatile option especially when in low light or when a very shallow depth of field is required or to simply create a blurred out background.
Therefore, whatever lens you decide to buy, you will be able to adjust it from its maximum Aperture Value to its smallest Aperture Value simply by using the aperture control within the camera.