Wednesday, 29 August 2012

Depth of Field in Portrait Photography

How to Control Depth of Field in Camera

Creative use of depth of field is one of the critical elements that could make or break a good portrait. How much of the subject or the surroundings should be in focus is determined by what the photographer aims to convey through the image. If the shot is just a picture of a person then using shallow depth of field will help blur the background and make the subject stand out; but if you are planning to do an environmental portrait then using a narrow aperture is recommended to get most of the elements in the surroundings to be in focus. A good knowledge about depth of field and how to control it to suit the various situations is very essential in portrait photography.

 Portrait Photography
Photo By Edgar Barany

Photography is also a process of elimination; many times you will find objects in your frame you wish were not there. There are many ways to get those items out of the frame; one other alternative is a controlled depth of field.

Depth of field in a shot is determined by many factors, it is to be understood that the more the crop factor of your digital camera’s sensor, the larger the depth of field. That is a point and shoot camera will have more depth of field than a DSLR with a crop sensor which in turn will have more depth of field than a DSLR with a full frame sensor. When distance from subject to the lens increases so does the depth of field and vice versa.

Depth of Field in Portrait Photography
Photo By Len Radin

Equipment for Portrait Photography

A DSLR and a portrait lens is the ideal equipment for portraiture. A DSLR gives you complete control over the three variables that control Exposure namely Aperture, Shutter Speed and ISO there by allowing you to control each element precisely to bring about the desired effect in your photographs.

depth of field in portraiture
Photo By Andy Leddy

By portrait lens photographers generally means lens in the focal range of 50mm to 135mm, 85mm being the most preferred focal length for portraiture. Apart from the focal length the most important requirement for a portrait lens is its widest aperture; the wider the aperture the better as it offers more scope for creatively controlling depth of field. Any lens with an aperture wider than or equal to f/2.8 is ideal for portraits of individuals.

Photo By Martin Muller

In the earlier days of photography, prime lenses were considered the ultimate in image quality and sharpness. But now a day most major camera manufacturers have high quality zoom lenses in their lineup that could match the performance of prime lenses in the same focal length. A zoom lens enables the photographer to compose easily without physically moving around much. It also reduces the need to change lenses frequently there by making the photo taking process much more enjoyable.

Depth of Field
Photo By Andy Leddy

Having said this it is also very much possible to create great portraits using a simple point and shoot camera. Although you will not have at your disposal a lot of creative controls, you have what is required to take good pictures. The situations which calls for the advanced features of the DSLR’s and their Lenses and actually rare, most of the time you could get away with a point and shoot. However when you have limitations in terms of gear, you need to compensate for it in terms of photographic knowledge, know the elements and also know your gear, its strengths and weaknesses, then you will know how best you could use them in any given situation.

How to Control Depth of Field in Camera

The easiest method to control depth of field in a shot is to put the camera to Aperture Priority mode. In Aperture priority mode you decide the aperture value and the camera fills in the shutter speed required for the lighting conditions present.

 Portrait Photography
Photo By Kaan Kiran

It is to be noted that when photographers say wider apertures or say larger apertures they are referring to smaller f numbers like f/1.4 and f/2.8 and when they say smaller or narrower aperture they are referring to numbers like f/16 and f/22. So a larger aperture is denoted by a smaller number and a smaller aperture is denoted by a larger number. The larger the aperture (smaller f number, f/1.4, f/2.8) the shallower the depth of field and the smaller the aperture (larger f number, f/16, f/22) the greater the depth of field.

Depth of Field in Portrait Photography
Photo By Amir Kuckovic

Now that you know what is depth of field and how to set it in your camera it’s time to practice. Find a subject, put your camera to aperture priority mode and take shots with varying aperture values. Study those images in your computer and observe the difference in each shot caused by changes in aperture values. With a few more trials like this you will easily get a hang of things and will be able to guess the aperture value required when you encounter similar scenes in future.

In the next article we will discuss about Photography - Portrait Photography - Group Photography - Ideas, Tips and Techniques

Related Reading