What is Aperture in Photography?

Simply put, aperture is how large the opening of your lens is. A smaller opening will let in less light, leaving more of your photo in focus as opposed to a larger opening (smaller number) will allow for MORE light into your photo and will cause your image to have a greater depth of field. Using a lens with a “fast” aperture of F/1.8 is often how photographers are creating images with bokeh.

Large aperture = Small f-number = Shallow (small) depth of field

Small aperture = Larger f-number = Deeper (larger) depth of field

What is Depth of Field?

The dictionary defines depth of field as following: the distance between the nearest and the furthest objects that give an image judged to be in focus in a camera. Another way to look at depth of field would be the amount of bokeh or blur in the background as opposed to sharpness in the foreground.

Why Can’t I Find the 1.8 Setting On My Camera?

This setting depends strictly on your lens! Most kit lenses have what will call a variable aperture. An example of this would be a lens that is marked as F/3.5-F5.6. This means that the largest aperture available on the lens depends on if you are zoomed in or not. We don’t recommend buying these lenses. However, they’re great for learning if it came with your camera. Another reason that you can’t find this setting is simply because your lens is limited to a higher number.  When shopping for a lens, this becomes a big factor.

When to Use a Small Aperture

Keep in mind that a SMALL aperture is a larger F-Number. With that being said, we would want to use a number of about 3.5-4.5 to photograph a group of people. The reason for this is so that everybody will be in focus. There’s nothing worse than a shot where only two out of five people are in focus.

In this image, I decided that I wanted the entire building in focus, so it was shot around F/9.

what is aperture in photography
In this image, a smaller aperture is needed to ensure that the entire image is in focus.

When to Use a Large Aperture

As opposed to the previous example, a LARGE aperture is a smaller F-Number. This means that less will be in focus, but we will have a greater depth of field. This is also exaggerated or “compressed” with larger focal lengths, but. We’ll get to that in a later video. Our example here would be if we wanted to photograph a single model and blur out distracting elements or even as a creative decision, achieving an image with beautiful bokeh.  You can also check out this post to see more tips and tricks to create a blurry image in your photographs.

In this image, the background elements were distracting from my primary focus of the couple. So a larger Aperture (smaller FStop number) was needed to create this image.

This Information And More Featured In Photography 101.

This portion of the exposure triangle and understanding its magnificence, is a small portion of my Photography 101 Course that you can, for a limited time only, be a life-time member of for only $45. That’s a steal, and so much more effective than buying books. This video series is continually growing and I’d love for you to be a part of our tribe! Learn more about the course by checking out this page..


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