|Photograph of a beautiful Catholic Church at different distances and focal lengths.|
One of the things which I frequently encourage people to do is to take a picture, then change something and take the same picture again. Examine the two images and determine in what ways they are similar, but more importantly, different. Then try to understand the reason why they are different, and you will have learned something.
You can do this with anything in photography really; ISO, exposure, white balance, shutter speed and aperture settings, and so on. In the shots above, I changes my position relative to the subject (the church) and focal length I used to capture the image.
The left image used a 31 mm focal length on an APS-C sensor camera so it had a relative focal length of about 46 mm - in other words it looked "normal" (as it appears to your eye). The right image used a 16 mm focal length, which has a relative focal length of 24 mm. This is a wide angle setting, and it alters perspective. You will notice that the entrance way appears much larger in the second shot and the spire seems much higher in the first. This has to do with perspective; the way that different focal lengths alter the image, rendering near and distant features differently.