This series of photographs shows basically the same subject taken with different focal lengths. I tried to get the exact same framing, moving closer or further to keep Andy in the same position in the final photo. Yeah, I know didn't frame them absolutely identical, but look at the difference in the photos. Keep in mind I was moving further away with each photo, and my eyeballs aren't perfectly calibrated.
Watch what happens to the depth of field (set to f 8 on all lenses). As you go through the photos, pay attention to the changes to the background. The differences in the field of view can be clearly seen if you keep your eyes on what happens to the sidewalk and neighborhood houses.
Starting with the wide angle view of 16mm, I was right next to the van. You can see the neighborhood street and lots of houses in the background. The field of view is pretty wide here.
At 35mm, you already see the street and houses beginning to disappear. The street sign and house behind it still seem fairly distant. The field of view is reduced.
The last photo is 500mm, into the super-telephoto range. Andy and the back of the van are the only things in focus. The tree and the house look like they are just behind him. This is the narrowest field of view.
You need to think about the differences when you decide which lens you attach to the front of your camera. I hope these blogs about lens characteristics helped you get your brain around why you would want multiple lenses to give you the most flexibility in your photography or which lens focal range is best for you.
Winner! Thanks for your comments, and keep them coming here and on our Facebook page. Marcy won the Light It. Shoot It. Retouch It. three DVD set from Kelby Training. It retails for $199.99. Contact Roger, and we'll make sure you get it.