I took some shots of a Bald Eagle using two different lenses. One is a 50mm f/1.8 and the other is a 28-135mm f/3.5-5.6 IS. The things that are the same about these photos are that I used a tripod, a white balance card, and am in the same location for both shots. As far as editing, I scaled down both images and that is it.
The best from the 50mm lens:
ISO 100 50mm f/1.8 1/320
From the 28-135mm lens:
ISO 100 135mm f/5.6 1/13
In this case I liked the result from the longer lens. If I was to keep the photo from the 50mm lens, I would crop the image, but I didn’t in this case because I wanted to show how well that lens blurs the background.