In just a couple of weeks a colleague of mine and I will be teaching our first Rock That Kid Shot Workshop. It’s a workshop for people who want to learn how to use that DSLR they bought, and now to take a better image of their own children. Something all parents should learn how to do. You will be grateful for doing it one day. You can read more about it here. Anyways, since embarking on a new challenge that is teaching I’ve decided to add some basic technical fundamentals to my blog. Starting today with depth of field. It’s a common question I get as a photographer. How do you get that blurry back ground in an image. Well, here’s my take on it.
Depth of field is the amount of distance between the nearest and farthest objects that appear in an image. For example, in the below image, my son is sharp and in focus but the background is blurry and out of focus. That was intentional in taking the shot.
Now this image is somewhat snapshotty (yes that is a word), but it shows how I wanted my son to be the focus with a lot of depth of field. He is the focus of the image. To achieve this I used a very large aperture. The aperture sits inside the lens and controls how much light passes through the lens. A large aperture lets through quite a lot of light and a small aperture lets though less light. They are described as f stop numbers. In this image a used a somewhat larger f-stop, 4.0. The smaller the f-stop number the larger the aperture, giving off more light. The larger the f-stop number the smaller the aperture, giving off less light. A bit confusing right? Here is a diagram to make a little more clear.
As a portrait photographer I tend to shoot as wide open as possible, which means I am shooting on a very low f-stop number. Usually between f/1.4 to f2.8, depending on my lighting situation. I love the look of a blurry background and having the subject sharp in focus. I find it adds more drama to an image, and is my personal style. There are certain occasions where a large f-stop would be warranted. For instance if you wanted the entire image in focus and sharp. Let’s say in a landscape image. The below image was one that I took while my husband and I were living in Argentina. It is a billboard and a light pole. I found quite interesting to look at and wanted the entire image in focus without any blur, so I used an aperture of f/11.
Aperture is definitely one of the technical aspects of photography that I think of with every single shot. Aside for the composition I always want ensure my aperture is where I want it so understanding how it works is vital to understanding how your camera works.
If you enjoyed reading about this blog post and have particular question about the technical side of photographer, please feel free to ask me. I’d be happy to make a post to answer your question. Next topic will be shutter speed!
