Zeiss 55/1.8 is not a different dimension, it's just better picture quality than Sony 50/1.8 or Zeiss 50/1.4 for Minolta A. If you're wondering whether to spend money or not, spend better on straightening your arms. And if finances allow, then buy only the best. Pros: Divine picture, soft and detailed. Light weight and dimensions. Cons: Friging. The absence of controls on the body - only focusing. Price tag.