03-03-2020, 02:50 PM
(This post was last modified: 03-03-2020, 02:55 PM by Brightcolours.)
(03-03-2020, 01:45 PM)Klaus Wrote: A shop used it. Feel free to search for it. :-)STM is not about the "rods" (guide bars). STM is about the motor, and the lead screw it rotates in case of the lead screw STM lenses (the geared STM lenses have no guide bars). The guide bars are just guides for the movement of the assembly, as they are with nano USM and some other manufacturer's systems (Fujifilm Linear Motor, Sony XD linear motor come to mind).
If you read the Canon Asia the statement isn't wrong really. Nano USM is still ultrasonic after all and it uses a guide bar system similar to STM.
It does not use the two different motors but uses elements of both systems.
The statement was wrong in that there is no ring USM motor at all, and no STM at all. So it was all wrong, what is why I pointed it out as error in the review text. ;-)
It uses no element of either the ring type USM or any STM. The only thing it has in common with ring type USM is that it uses vibrational energy to generate movement. But the way they go about that is very different (linear vs rotational)...
In Canon Asia's words: " Unlike the other two USMs, it is a direct-drive system: Ultrasonic vibrations are directly transmitted from the piezoelectric element to the slider, which moves the focusing lenses (mounted on a rack assembly) in a back-and-forth direction."