What is depth of field?

Depth of field is a commonly used term in photography. We all use it, but what does it actually mean? Time to focus on this topic.

Depth of field

Imagine you have a vegetable patch, and you want to photograph a tomato. Let say there's just been a rainstorm and the tomato still has droplets of water on it. Time for a photo! The droplets of water on the tomato are nicely in focus whilst the rest of the tomatoes hanging from the same vine, are out of focus. The part in focus in your photo is called depth of field. Simply put: depth of field is the area that is in focus from a near point up to a point farther away. So it's not only the point you focused in on that is the only part that's in focus. There is still an area in focus, in front and behind that. How big that area is depends on a number of points: aperture, focal point and distance. These points affect how we experience depth of field.

Back to the tomato. As only a small area is in focus, in this case the tomato, we're talking about minimal depth of field. Now take the same tomato and place it in a greenhouse among tomato plants. You don't want to see a particular section of space, but the entire greenhouse. This is called large depth of field. Everything is sharply depicted; from front to back.

Large depth of field is therefore often seen in landscape and architectural photography. That's when you want to see all there is to see on your photo. Small depth of field is more prevalent in portrait and macrophotography.

Why depth of field?

When viewing a photograph, your eyes will always go to the sharpest part first. There's nothing you can do about this, it's automatic. By playing around with the depth of field, you can direct the viewer's eyes. You can highlight something to the viewer, in other words: tell a story with the photo. With some parts out of focus the photo can get more mysterious, because you can’t exactly see what’s goin on in some parts of the photo.

Playing around with aperture and depth of field

We'd just like to mention the importance of aperture, focal point and distance from the object again. After that, you can get on with experimenting with depth of field. The aperture relates to the lens' opening. In that opening there are several blades that slide on top of each other. These blades are used to increase or decrease the size of the opening. Good to keep in mind with this is that the smaller the aperture, the larger the area of focus becomes. So, with a large aperture you get small depth of field. There's more to aperture than this, but in terms of depth of field this is the most important thing you need to know for now. The focal point and distance are actually connected. These two words are usually combined into one: focal distance.

With focal distance we try to ascertain the distance from the photographer to the subject in order to set the right settings. The focal distance is the point where all light merges together on your camera's sensor. Often the focal distance of your lens is identifiable by the number of mm inscribed on the lens. The focal distance determines how much can be seen in your photos and how much the subject will be in focus. It's up to you how much you want to show on your photograph.

What is bokeh?

You've probably come across the word bokeh before. Bokeh comes from the Japanese word boke and means out of focus. When we talk about bokeh we're actually talking about the quality of the blur in your photo. By quality, we mean the degree to which round shapes and colours merge with each other. Bokeh, therefore, only occurs with small depth of field.