Every lens has its sharpest aperture also known as your Len's sweet spot. In an article by Dena Haines from Digital-Photography-School.com, this article clearly explains and answers:
1. What is a len's sweet spot
2. Should you always use your len's sweet spot?
3. How to find your len's sharpest aperture - 2 methods
4. Why are my Images are still blurred!?
You can read the full article at this location : HERE
