[quote name='Klaus' timestamp='1340646426' post='19099']
It was news to me that STM mean by-wire.
Personally I never had issues with this approach anyway.
[/quote]
Lenses with a stepper motor ("STM" means "stepper motor") have no clutch nor reduction gear to avoid any play which would perturb the functioning of the contrast detection autofocus. So you can't expect actioning the helical mechanically.
It was news to me that STM mean by-wire.
Personally I never had issues with this approach anyway.
[/quote]
Lenses with a stepper motor ("STM" means "stepper motor") have no clutch nor reduction gear to avoid any play which would perturb the functioning of the contrast detection autofocus. So you can't expect actioning the helical mechanically.