Few days ago I went and purchased the Canon EF 50mm f1.8 STM along with the ES 68 Lens Hood. I absolutely in love as to how quiet this lens is when shooting with my EOS 40D, at wide open the bokeh is cleaner than the old f1.8 II plastic fantastic version. Friday was the first day shooting with this lens and I love the accuracy of the autofocus and the price. At $189 Canadian or 109.55 British Pound there is no other 50mm at such a bargain. Even, with the f1.4 version, that lens needs to be stopped down to f1.8 to get the same result as the STM at full aperture. Why spend more for a lens that gives you the same results? Features of the EF 50mm f1.8 STM: 7 rounded Aperture Blades as oppose to 5 non-rounded found in the f1.8 MKII. Metal lens mount vs plastic Improved overall build quality Super Spectra Coating Improved Manual Focusing Ring STM (Stepless Motor) vs Micro-Motor on f1.8 MKII for quieter and smoother operation. Full time Manual Focusing as long as the shutter button is pressed half-way. 0.21 Magnification vs 0.15 found on the older version Stops down to f22 as opposed to f16 found in the MKII. Bayonet lens hood.