There are number of debates and confusions whether to use longer lens or shorter lens (also known as wide angle lens) to shoot portraits. After doing little bit of a research and reading few books, I have decided to write a blog about it. There are couple of factors to be considered while comparing a longer lens vs. a shorter lens for portrait photography. Let me explain them briefly and hope it will help you to find your answer as well.
When you use a wide angle lens, you have to get closer to the subject to fill the frame. This closer distance to the subject creates distortion to the picture; things on the foreground look too big and things on the background look too small. If you are shooting people with shorter lens, you will get odd shape body of person like big flat face, long nose and other unstructured shape which you never think would come out as a result. Whereas if you use longer lens which requires farther distance to the subject minimize that distortion and things will have more realistic perspective. It also allows your portrait subject to sit comfortably as you maintain reasonable distance to the subject because of focal length.
2. Angle of view
Angle of view is simply how much you can see from view finder (or say how much you get inside frame) using different types of lenses. Wide angle lens or shorter lens will give you wide angle of view and hence you can see much more things on the background which can create cluttered images. But longer lens will give you narrow angle of view and you can see minimum of the background and foreground will be focused and almost entirely framed in the picture which helps to produce nice and clean shot.
3. Ease of use
Also if you are working with long zoom lens, you have another advantage to use it over fix length lens or shorter lens. It will allow you to shoot medium length shot to close head shot without moving front and back. You can use 50mm lens for general portraits but if you take closer headshot using this lens, you will end up getting little cartoonish character face than real face. We consider 85mm-135mm lenses ideal for portrait photography but you can also use 24-70mm f/2.8 or 70mm-200mm f/2.8 zoom lens but keep in mind their weight while using them for long time shooting.
Conclusion: Wide angle lens exaggerate things on your photographs. In fact wide angle lenses are not designed to use in portrait shot. They can be best use while shooting landscapes, interior where you want to capture much more things. Any lens between 85mm-135mm focal distance is considered the best lens for portrait photography which will keep your images clean, remove clutter from the images, keep nice distance with the subject, allow you to shoot multiple shot without moving front and back. And also creates nice shallow depth of field so that your foreground will be separated from the background producing pleasant image.