Understanding Aperture

Without question, this is the most talked about subject, because aperture either adds dimension to a photograph by blurring the background, or magically brings everything in focus.

Aperture is a hole within a lens, through which light travels into the camera body.

The iris of the lens that controls the size of the aperture is called a diaphragm in optics. The sole purpose of the diaphragm is to stop all light, with the exception of the light that goes through the aperture. In photography, aperture is expressed in f-numbers (for example f/1.8). These f-numbers that are known as f-stops are a way of describing the size of the aperture, or how open or closed the aperture is. A smaller f-stop means a larger aperture, while a larger f-stop means a smaller aperture.
 People find this to be very awkward, since we are used to having larger numbers represent larger values, but not when it comes to aperture. For example, f/1.2 is larger than f/1.8 and much larger than f/11.

This is where depth of field comes into play (which is what helps create dimension in your images).

The size of the aperture is what directly impacts the depth of field, which is the area of the image that appears sharp.A large f-number such as f/22, (which means a smaller aperture) will bring all foreground and background objects in focus, while a small f-number such as f/1.8 will isolate the foreground from the background by making the foreground objects sharp and the background blurry.

Please note that each lens will have/ can have a different minimum and maximum aperture.
For example my Canon 24-105mm lens has a Maximum Aperture of f/4.0 and a Minimum Aperture of f/22.
My Canon 85mm lens has a Maximum Aperture of f/1.8 and a Minimum Aperture of f/22.

Which leads me to my next sub-subject within Aperture...
Each lens has a limit on how large or how small the aperture can get. If you take a look at the specifications of your lens, it should say what the maximum (lowest f-number = smaller #) and minimum apertures (highest f-number = larger #) of your lens are. The maximum aperture of the lens is much more important than the minimum, because it shows the speed of the lens. A lens that has an aperture of f/1.2 or f/1.4 as the maximum aperture is considered to be a fast lens, because it can pass through more light than a lens with a maximum aperture of f/4.0. That’s why lenses with large apertures are better suited for low light photography.

If you have any questions on Aperture, please feel free to list them below!

Thanks for reading!

Tori D.



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