Sometimes, Image Sharpness is a Handholding Problem
Sometimes our assumptions about handholding the camera are misplaced— recently I worked with a client to diagnose a sharpness issue, which he had assumed to be a lens sharpness issue. But it turned out to be too-low shutter speed.
Among many topics, the How To Banish Blur Whether Handheld or Tripod section in Making Sharp Images offers a discussion of how to hold a camera steady.
With high resolution digital, technique errors can easily outweigh moderate optical differences.
