EOS 7D MK II
- Feb 25, 2015
Just like there are multiple USM types (regular, ring, nano), there are multiple STM types, have a look at https://www.eos-magazine.com/articles/EOS_feature/canon-stm-stepping-motor-lens.html .Well, that is simply not what I experience, having STM lens, old USM lens and new USM lens. I'm afraid your statement is more from marketing materials and official articles than actual real life use.
So non-ring USM compared to lead-screw STM would likely favour STM for speed and noise. Canon is quite blatant in their press materials, after a while you start to notice that on select lenses they will say "But this one uses the awesome version of <focus tech>", while the other lenses just get the generic blurb.