I went to Wikipedia to see if they could tell me what an ultrasonic motor is, how it works, and whether it can be heard.
That last point was my first question actually. Seeing the term “ultrasonic” triggered the thought that the sonic may be “ultra” with respect to human hearing, but maybe birds and other animals can hear and be alerted by the ultrasound? I suspect probably not, but Wikipedia did not address this. The Wikipedia article is written for someone with a technical background and I found it unintelligible. However, they do include a list of common application of this technology, autofocus lenses, pioneered by Canon. With several other companies now using the technology under various names including Sigma HSM, Tamron USD, PZD, Nikon SWM, Olympus SWD, and Pentax SDM. stan > On Jul 27, 2016, at 7:17 PM, Alex Sarbu <alexandru.sa...@gmail.com> wrote: > > The HD Pentax D FA* 70-200mmF2.8 ED DC AW doesn't use the same type of > SDM micromotors as the DA*-series lenses. Actually it doesn't use SDM > at all - but DC motors. Fast, reliable. > > Last Pentax lens with these SDM micromotors was announced in 2008. > Since then we had 3 K-mount "SDM" lenses, all using Tamron's > "ultrasonic"-type motors (in case of the D FA 24-70 and 15-30, > ring-type "ultrasonic" motors). > > Alex > > On Thu, Jul 28, 2016 at 1:21 AM, Gonz <rgonzoma...@gmail.com> wrote: >> Hmmm nice deal. Is this lens one of the ones that has the unreliable >> SDM focusing mechanism I heard about with the 60-250 or such? >> >> >> >> On Wed, Jul 27, 2016 at 5:05 PM, Igor PDML-StR <pdml...@komkon.org> wrote: >>> >>> Hi All, >>> >>> Just in case someone is shopping for lenses... >>> B&H has some sale on Pentax items. I don't know how good all the prices are, >>> - but D FA* 70-200mm/2.8 is only $1696, which is $100 lower than what is was >>> going for (1800). >>> Adorama has the same price for this lens. >>> >>> Here are other sale items: >>> http://www.bhphotovideo.com/c/buy/items/ci/32002/ipp/48/N/3638625979/view/GRID >>> >>> HTH, >>> >>> Igor >>> >>> >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> PDML@pdml.net >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. >> >> >> >> -- >> -- Reduce your Government Footprint >> >> -- >> PDML Pentax-Discuss Mail List >> PDML@pdml.net >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
