Photography and commentary from John Fujimagari

The F Stops Here


Or Understanding Aperture

Cape May Warbler

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.

Near The Pipestone

 

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.

 

1.4 2.8 5.6 11 22
2.0 4.0 8.0 16 32
1.4 2.0 2.8 4.0 5.6 8.0 11 16 22 32
The smaller the number, the larger the opening of the lens and more light comes in. A larger number means a smaller aperture. This also affects Depth of Field (DoF) or how much is in focus. An easy way to think of DoF is people. Stand them one behind the other. If you want more people in focus, choose a larger number, less people a smaller number. Of course, the numbers won’t correspond directly.
Lens choice also affects DoF, wide angles generally give more, telephotos less. Also, the closer you are to your subject the more your DoF will be reduced.

Sunset And Water 2

 

At f/4.0 and 60mm the distant scene is rendered mostly in focus. So does that make things clear?

In the best light…

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