Exercise: Focal lengths and different viewpoints

For this exercise I decided to use my 18-200 Canon lens. I believe it's the ideal lens for this purpose as it goes as wide as 18mm and zooms at 200 mm.

I chose an abandoneed train as the subject and framed it vertically.I zoomed at 200 mm and backed up untill it was close to the edge of the frame.

This is the view I have when taking a picture at a focal length of 18mm.

This is in the same position but at a focal length of 200 mm.

I started walking in a straight line looking through the viewfinder at a focal length of 18mm. It surprised me how close I had to get to the object to fill in the frame. I was only a few inches away when I took this next shot.

It took around 47 foot steps to get to this point. The difference in perspective is amazing. Now I realise how different it is to shoot a same object from the perspective of a wide angle or a telephoto. In this situation the wide angle makes the train appear much bigger and gives depth to the image. In the telephoto version the image is compressed and looks very flat. it's hard to tell how far are the background elements as opposed to the wide angle.