Beat Lens Distortion

No matter how good the setup, how perfect the lighting, how photogenic the model, it will all be wasted with the wrong lens or zoom setting. With compact cameras having as low wide angle settings as 25mm at 1x zoom, and DSLRs with kit lenses starting at 18mm, lens distortion can send otherwise perfect pictures heading to the recycle bin.

Lens distortion shows itself worst when capturing images of people. A nice panaramic shot from the top of a hill or across a lake, will benefit from a wide angle setting, and any horizon distortion is easy to fix during the editing process. People have a disadvantage in this area because we have protruding features, like forehead, nose, chin and ears.

Take a look at the portrait on the right, this was taken on a wide setting of 17mm which has created quite a comical, and unflattering effect.

This lens setting has caused the ears to move back and inwards, while the nose chin and forehead are stretched out towards the center of the picture.

It is not only the width of the face that has been affected, it has also been elongated vertically, and because the camera had to be so close to fill the frame, the models eyes are slightly crossed

The equipment used in this test:

• 50mm f2.8 DG Macro
• 105mm f2.8 DG Macro
• 17-70mm f2.8 4.5 Macro.
• Canon 400D

Image number 1 Shot at 70mm

This is the test image using the 70mm end of the 17-70mm lens. The canon 400D does not have a 35mm full frame sensor, so a multiplying effect of x1.6 is applied, which means that a lens of 70mm will produce an image with the equivalent of a 112mm setting.

The appearance of the image is good but the features of the face do seem a little flat. Even though the head is turned slightly the ears do appear a little wide.

The overall picture has a very natural feel and look to it. In most situations this would be considered as a good reproduction of the subject with no noticeable distortion. It will be interesting to see how it compares to the other photos.

Image number 2 shot at 105mm
With the x1.6 multiplying effect of the camera this picture has an effective focal length of nearly 170mm, and the distortion in this image has become more noticeable.

The head has been squashed down making the face become more rounded, and the depth of the picture has decreased, causing the image to look very flat. This is most obvious when looking at the ears, they appear to be pulled forwards and out almost to the same level as the eyes.

Also at this focal length the focus is starting to run out, which is apparent when looking at the ears and noticing the blur that is appearing.

The 50mm Test Image

This last shot was taken using the 50mm lens, when adding the x1.6 multiplying effect this equates to a figure of 80mm. This is considered right in the safety zone as far as portrait focal lengths are concerned.

An actual focal length between 70mm and 100mm will produce a good portrait reproduction, with good depth and natural looking features.

Although these focal lengths produce natural looking features, there is no reason why the rules can’t be broken. A longer focal length could be used to de-emphasize a long nose or a short lens used to try and give depth to a flat face.

Whatever focal length is used, if we can make the people around us smile with the way we represent them in our pictures, then we’ve done our job well.