In Exercise 2.3, the aim was to take a low close viewpoint and use a wide angle lens to show perspective distortion. From the image you can see that a very wide lens together with a close view point creates extreme perspective distortion. With regards to this photo the exaggerating and unrealistic features are the stomach and chin. The spaces appear to expand. The low viewpoint adds a sense of momentality, making the subject seem larger than it is. Wide angle lenses are not used for portraits.
This image has perspective distortion. Unlike optical distortion, it has nothing to do with lens optics and thus, it is not a lens error.
When projecting three dimensional space into a two dimensional image, if the subject is too close to the camera, it can appear disproportionately large or distorted when compared to the objects in the background. This is a very normal occurrence and something you can easily see with your own eyes.
If you take a smaller object like a pen, then bring it very close to your eyes, it will appear large relative to say your big screen TV in the background (and the farther the pen is from your TV, the smaller the TV will appear relative to the pen). The same thing can happen when photographing any subject, including people.
An example of optical distortion is called ‘Barrel distortion’ This is when the straight lines are curved inwards in the shape of a barrel. This is commonly seen in wide angle lenses. Barrel distortion happens because the field of view of the lens is much wider than the size of the image sensor and hence the image needs to be squeezed in to fit. A fish eye lens is an example of optical distortion.
Barrel distortion can be decreased significantly by using compensating optical elements or by post processing.
I went through my archives to see if I could find any distorted perspective images.
In this image the boys head appears disproportionately large relative to his body. His sunglasses, chin, nose and lips are very much enlarged, while his ears are dwarfed. If I got closer to his face or used a wider lens at a shorter distance these distortions would be worse.