How to get shallow depth-of-field effects with any camera

Many photographers turn to full-frame cameras and fast lenses to get shallow depth of field, but what if you only have a smartphone or a basic compact? Here’s what you need to know.

While it certainly helps to have a camera with a large sensor and a wide-aperture lens when trying to achieve shallow depth of field, it’s still possible to achieve this to some degree on cheaper compacts and cameraphones without resorting to digital manipulation.

Developing an understanding of how subject and focusing distances affect depth of field is useful to know whatever camera you use, so read on to see how you can maximise this in your images.

Get close to your subject
If you’ve ever used a macro lens you may already appreciate how focusing closely on a subject affects depth of field.

Whereas, for example, a 90mm lens used conventionally for a portrait will may give shallow depth of field at a given aperture, a macro lens of the same focal length will produce only a very fine sliver of sharpness when used to shoot a subject only a few cm away at the same aperture.

This isn’t limited to macro lenses, however, just that they are designed to focus much closer than conventional optics, so the effect is much easier to see when using them.

Modern smartphones and tablets can capture subjects just a few cm away, so even with their smaller sensors they can render backgrounds pleasingly blurred. Compact cameras may not be able to focus down to the same distances at conventional settings, which leads us on to the next step…

Use the macro mode
The majority of compact cameras offer a macro option, usually marked by an icon of a flower. When set to this mode the camera is instructed to focus closer than usual to a subject, perhaps just a cm away or so.

With focus so close, priority is not being placed on more distant subjects, so anything away from the subject will naturally appear out of focus as a result.

Most cameras will require you to switch to the wideangle setting when using the macro mode, as they will not be able to focus this closely when using longer focal lengths.

Bear in mind that capturing images up close with a wideangle lens could lead to your subject being distorted, so either watch this as you shoot and adjust your position or try to rectify this using some kind of distortion correction.

Separate the background as much as you can
Whenever you focus on a subject you instruct the camera what part of the scene is the priority. However, the camera will not only focus on the subject alone, but will extend focus to a zone behind and in front of the subject too, which is partly determined by the aperture you use.

This means that anything in the same area will also be rendered in focus, gradually becoming more blurred as you get further away from wherever you’ve chosen to focus. So it follows that background (or foreground) details further away from the subject will be blurred to a greater extent than those closer to it.

Bear this in mind when it comes to framing your shot, moving anything that may distract from the subject out of the way if possible and changing your position so that the background details are as far away as possible.

Choose a different focal length
Longer focal lengths are often thought to produce images with shallower depth of field than wider ones, although this isn’t quite the case.

It seems to be so, as you’d naturally opt for a long telephoto lens when isolating a subject from its background rather than a wideangle optic, but to make the comparison fair you would need to move so the main subject occupies the same proportion of the frame in each image you capture.

And if you did this, you would see that depth of field hardly changes between the two.

Yet, images appear to have more pronounced blur in shots captured with telephoto lenses – so what’s happening here? Basically, with a narrower angle of view, less of the background is being captured with the telephoto lens than it is with the wideangle lens.

As a result, what is being captured is essentially being stretched to a greater extent in order to fill the frame, which appears as stronger blur. Of course, for most people whether this technically creates more shallow depth of field or not is academic; it’s simply enough for it to appear this way.

If you’re using a compact camera, try zooming in as far as possible and capturing it from the minimum subject distance at which your camera will allow you to focus.

For subjects in a line, shoot at an angle
Strictly speaking, this method doesn’t create shallower depth of field although it works by using additional points of reference to highlight how shallow the depth of field actually is.

Let’s suppose you’re capturing a series of railings, and you’re standing perpendicular to them, focusing right in the centre of the frame.

As the entire railings are more or less all at the same distance away from you, they will all be recorded with roughly the same focus.

Now consider what would happen if you carried on focusing exactly where you were before but you moved to one side or another so that you were at a 45degree angle to the railings.

Some would be further away and some would now be closer to you, and with a sufficiently wide aperture you would be able to blur both to leave the middle of the frame focused.

Move to a more acute angle and this would increase even further. By filling the frame with subjects that you know will be out of focus, more attention is placed on the shallowness of the area that is in focus.

Obviously this won’t be appropriate for every scene, but it’s useful to know if you only want a very small part of the scene to be in focus.

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