birefringence said:What is ECF? Is it important to have?
Thanks!
on a sidenote, ECF is one of Canon's ingenious marketing devices groomed by the talented but misguided product engineers Canon employ and prepped to look good on a feature sheet, except in this case ECF wasn't nearly as effective a selling point as say, USM (which is ACTUALLY useful) or white L lenses (which gives character, and more importantly, looks darn good! ).