The F Stops Here
Or Understanding Aperture
A wide open lens can often render the background of an image blurry. Sometimes the subject is less cooperative. f/5.6 is wide open on my 400mm telephoto lens.
f/11 on a 17mm wide angle lens can give you front to back sharpness.
Aperture may seem like some mystical, magical photographic voodoo. It is quite simply a ratio of the focal length and the size of the opening of the lens. if you break it down a bit, it’s easy to figure out. If you look at the first and second rows separately, you can see that the numbers in each row are approximately double. The bottom row is the common aperture scale. Each column in the bottom row doubles the light coming through the lens opening if you move to the left. If you move to the right the light is halved. The top two rows are 2 stops apart each.
At f/4.0 and 60mm the distant scene is rendered mostly in focus. So does that make things clear?
In the best light…