<p>well , IQ is not everything, i think a conpact ais28/f2 brings more fun than AF 2.8 . 52MM FILTHER is also benifet in saving money. the focus feeling also better. i have a AI28F2.8, hevily used, spending 90USD. i bought a ais28 f.28 new for 450usd, after comparision i find no differenc e at all and return the ais one.</p>