This exercise shows how a low viewpoint and wide-angle lens creates extreme perspective distortion. ‘Gentle receding lines become diagonals and rounded forms bulge towards the camera. A low viewpoint and tilting the camera makes subjects seem larger than they are and vertical lines dramatically converge’. (Course notes p44)
I shoot in both raw and jpeg. Part of the processing of a jpeg image in-camera involves correction for lens distortion but in the raw image any distortion is visible.
Here are two images. The first is the jpeg I saved from the raw image without editing. The second is my camera’s jpeg image after in-camera processing. I include both images so that the effects of camera distortion are clearer.
You can see that in the first image, the gate is significantly bowed and the fence post appears bent. There is a clear ‘bulging’ of the image, as the lens makes the image appear convex. The jpeg image created by my camera has corrected these distortions so the second picture appears more as it did in reality.