Exercise: Focal lengths & Angle of view

18 mm f/5,6 1/125"

48 mm f/6,3 1/160"

300 mm f/5,6 1/500"

I took these pictures from my appartment. It was a rainnny and cold day and I decided to do some shooting at home. I took the normal view picture with 48 mm focal length. 

Then I usen 18 mm focal length as wide-angle. Both pictures were taken with my Nikkor 18.0-55.0 mm f/3.5-5.6 zoom lens. Then, I changed to the Nikkor 70.0-300.0 mm f/4.0-5.6 telephoto lens and made two pictures, one at 70 mm focal length and the other at 300 mm (max and minimum focal lengths). I used a tripod so all pictures were taken from the same position.

Then, I printed all the pictures and went to the balcony. I took the 48 mm picture and realized that I felt comfortable when the picture was at about 45 cm from my eyes. If the picture got closer, all the elements in the picture were larger and if I moved away the picture all the elements in the picture were smaller. Then I took the 18 mm picture and repeated the process. The difference was that the picture needed to be nearer to me (about 18 cm) to have the same view as the picture. And just the opposite for the pictures taken with the telephoto lens. They needed to be further away (about 72 cm and 3 m respectively). So looking from the same distance the elements in the telephoto pictures look larger and the distance between the elements seems more compressed.