Stop it Down. Just a Bit.
If you read much that I write, you know I love’s me some wide-aperture prime lenses. I like the narrow depth of field that isolates my subject, and the ability to shoot in low light. More than anything else, though, I love a nice sharp lens with superb re
via LensRentals Blog: http://www.lensrentals.com/blog/2011/11/stop-it-down-just-a-bit
The takeaway pont, though, is for many wide-aperture primes, stopping down slightly, just to f/2.0 or so, will dramatically increase resolution. For others, stopping down makes little difference, especially in the center of the image. Like everything else in photography, the more you know about the specific lens you are shooting with, the better you can use it.