Portrait lenses
In principle, you can take perfectly acceptable pictures of people with any lens. But if you want to make your portraits stand out from the plethora of everyday smartphone snaps, then picking a lens capable of rendering a very different look will pay off. Conventionally, this often means choosing a short telephoto with a focal length in the 85mm to 135mm equivalent range and a large maximum aperture. Indeed the term ‘portrait lens’ is often used to describe such optics, which deliver head-and-shoulders shots with both a flattering perspective and a nicely blurred background.
However, there’s more to photographing people than this. With couples, for example, the wider view of a 50mm prime may be a better option, while for environmental portraits that show people in the context of their surroundings, a 35mm lens is often preferred. Going wider still with a 24mm can deliver striking results for full-body shots. It’s all about understanding how to use the properties of different optics to achieve your desired result.
Depth of field and bokeh
For portrait lenses, wide-open sharpness isn’t essential; indeed a little softness will often be flattering. But one genuinely desirable characteristic is the ability to concentrate attention on your subject by throwing the background out of focus. As most readers will know, this is done most easily using a long focal length and a large aperture, which generally means using a prime rather than zoom. But the flip-side is decreased depth of field, and shooting portraits with just one eye in focus isn’t always a desirable look. So it’s worth understanding that by separating your subject from the background and using a longer lens, you can use a relatively small aperture to increase depth of field while maintaining a high level of out-of-focus blur.
It’s not just the degree of background blur that counts though, but also how it looks. This is where the concept of ‘bokeh’ comes in. This much-abused word originates in Japanese and is used to describe how the aesthetic quality of the blur differs between lenses, even if they have the same physical specification. Some may deliver smoother blur,
