How to get a blurred background in photos

Somewhere at the start of the adventure that is photography, a newer photographer will soon realize that having your subject stand out from the background, really gives the photo a near-3-dimensional effect. Your subject just pops out with the background blurred. The question of how to get blurred backgrounds in photos, is easily answered.

There are two ways to blur the background in a photography – In-camera (i.e., optical) vs Photoshop. Doing it in Photoshop is in my opinion, a boring way to spend an afternoon when you could be out shooting. Much more fun, and much more satisfying, is doing this in camera. The method in this case is quite easy – it comes down to lens and aperture choice.

Back in the day of film cameras, the camera would come with a standard lens – the 50mm lens. These lenses always had a fast aperture of f1.8 or so. If you shoot at a wide aperture, the background will go out of focus. There are other factors at play as well, and we will discuss them, but that’s the essential part – your choice of aperture. While 50mm lenses were the standard many decades ago, it is now more common to find slower zooms as the kit lens that comes with a camera. These lenses have apertures in the range of f/4 to f/5.6 … and they are relatively smaller apertures that make the background sharper.

So for a blurred background, it is up to us to control the aperture and our subject’s distance from the background.

Newer photographers, don’t be confused by the technical wording. Even though f/2.8 is numerically smaller than f/16, it is in fact the wider or larger aperture. In comparison, f/16 is a smaller aperture. The convention is to describe the aperture size (wide / large / small) in relation to the physical size of the lens opening, and not the numerical value. In other words, never describe f/2.8 as a smaller aperture than f/16 – stay with the accepted phrasing. This is important and not merely a pedantic point.

One of the best explanations of depth-of-field, is on the Cambridge in Color website. Well worth a visit if you want to get a handle on depth-of-field and aperture choice.

 

Things which control how blurred the background appears

Your choice of aperture – the wider your aperture, the more blurred your background.

Your choice of lens – the longer your lens, the more the background will appear to be blurred. There’s a caveat here though – for the same positioning of your subject in relation to the camera, the DoF will be the same for different focal lengths! But with the enlarged view of the longer lens, the background will still somehow appear to be more blurred, even if technically it isn’t when you do actual cropped comparisons. Still, we can comfortably say that the longer your focal length, the more blurred the background will appear.

The distance between your subject and the background. No use backing your subject up against something and then hoping to blur it. Have your subject step well forward of things. The further the better.

The optical quality of your lens known as ‘bokeh’ – a description of how the background blur is rendered. Some lenses will, for the same aperture, give a smoother rendition than other lenses which might show a more harsh rendition of the background. More info here: Bokeh vs shallow depth-of-field (DoF).

 

Camera settings & photo gear (or equivalents) used

• Left: 1/4000 @ f/1.4 @ 100 ISO
• Right: 1/1000 @ f/2 @ 100 ISO
• Both images shot with available light only.

• Nikon D810
• Sigma 50mm f/1.4 ART for Nikon:  B&H  /  Amazon
• Sigma 50mm f/1.4 ART for Canon:  B&H  /  Amazon

 

Summary

The larger your aperture, and the longer your lens (with your subject at a distance from the background), is the recipe to get a blurred background to your photos. It need not be a 50mm lens or a fast 85mm lens – a longer f/2.8 (or even f/4) zoom lens in the 70-200mm range, will give you that kind of effect with shallow depth-of-field.

Check these two articles for further reference:

• Making your images pop through lens choice – Compressed perspective
• 85mm – The best lens to change your portrait photography

 

Using an 85mm lens as a shallow depth-of-field portrait lens

This photograph was shot at f/1.6 with an 85mm lens. It is even better than the 50mm lens in giving a more pleasing portrait perspective:  85mm – The best lens to change your portrait photography.

Selective focusing / selective DoF gives a specific look that is very attractive, and can help draw attention specifically where you need it. With photos like this, an aperture f/22 would give a cluttered image …

… as the pull-back shot at f/5.6 already implies.

 

Related articles

• Bokeh vs shallow depth-of-field (DoF)
• Full-frame vs Crop-sensor comparison : Depth-of-field & perspective
• Making your images pop through lens choice – Compressed perspective
• Tips on improving your photography technique
• review: Canon 50mm lenses – bokeh
• Using narrow depth-of-field & lens bokeh

 

A bit of homework

It is going to be essential as part of your growth as a photographer to know at least the full-stop values of apertures, up and down. Better yet, know the 1/3rd stop indents off by heart. Up and down. It’s important.