Saturday, 31 August 2013

What Lens Should I Choose? Tips for choosing the right lens for portraits

portrait lens
Tips for choosing the right lens for portraits

In general portraits can be classified into three categories

1. Close up - head and shoulders portraits
2. Mid distance – ( ¾ ) three quarter length portraits and
3. Long distance – full length portraits

In order to avoid distortions and produce a natural perspective in your portraits it is essential to use the right focal length lens for each of the above portrait types. Here in this article we will discuss some practical guidelines for selecting the right focal length lens for each situation.

Why is using the right focal length lens important in portraiture?

If you use a wrong focal length lens when photographing a particular portrait pose, it will alter the perspective and result in distorted / wrongly proportioned facial / body features.

When using lenses of shorter focal length you need to move the camera closer to the subject to fill the frame;
If you are attempting a close up head and shoulders pose with a short focal length lens, it will cause the subject’s nose or other facial features to become slightly distorted. 

Similarly if you are shooting a three quarter length portrait with a lens of short focal length it will cause body parts which are closer to the camera (hands or feet resting in forward position) to appear too large.

When using lenses of longer focal length for portraits you will need to move the camera much farther from the subject to fit it in the frame. This causes an effect called compression where the image appears flattened and loses the feeling of depth and three- dimensionality.

Choosing the Right Lens for Portraiture

Lenses which have a focal length equivalent to the diagonal length of the sensor is considered a normal lens. So for a full frame DSLR camera which has sensor dimensions of 36mm * 24mm the diagonal length will be 43.3mm and hence any lens with a focal length in the range of 40mm – 50mm may be considered as a normal lens. If you are using a crop sensor camera then sensor sizes are slightly different from manufacturer to manufacture. Approximately APSC sensors are 16.7mm * 25.1mm and has a diagonal length of 30.1mm. So any lens in the focal length of 24mm-35mm may be considered as a normal lens.

The peculiarity of a normal lens is that it reproduces a field of view that generally looks "natural" to a human observer under normal viewing conditions, as compared with lenses with longer or shorter focal lengths which produce an expanded or contracted field of view that distorts the perspective.

Right Focal Length for Full Length Portraits

full length portrait
Photo by: xubangwen

In portraiture the so called normal lens is ideal for long shots or full length portraits. Subjects could be either standing or seated; it is also a great choice for photographing groups.

Right Focal Length for Head and Shoulders Portraits

head and shoulders portrait
Photo by: Garry Wilmore

For head and shoulders portraits (close up shot) it is recommended to use a focal length which is double that of the normal lens for your camera. So for a full frame camera you may use a focal length of 105mm as minimum and 135mm as maximum.

Right Focal Length Lens for (¾) Length Portraits 

three quarter length portrait
Photo by: Sean Molin

For three quarter length portraits use a focal length in between the full length and close up range. For full frame DSLR camera Focal lengths of 100mm – 105mm is considered ideal.