I believe the ultrasonic comes in because the linear motor uses
ultrasonic frequency AC current to operate. Using AC in the 30KHz to
100KHz range allows for a much smaller motor than DC or normal AC does.
BTW the switching power supply in your computer uses ultrasonic AC, but
they don't hype it like Canon does. Consider it an advertising buzz word
and don't get excited over it.
In comparison you could say Pentax uses a Hemi Motor for focusing. Old,
big, but powerful. And you don't have to have a separate motor for each
lens. Canon does not use those linear motors because they are better,
but because they are cheap (there is almost nothing to them). Such is
the power of advertising.
My camera has more buzz-words than your camera. Yadda, yadda, yadda....
graywolf
http://www.graywolfphoto.com
"Idiot Proof" <==> "Expert Proof"
-----------------------------------
Toralf Lund wrote:
DagT wrote:
Of course, we don´t hear ultrasound, but some animals do.
So, if you try to shoot them with a Canon, they'll run away???
Is there really anything ultrasonic about it, by the way?
Toralf was thinking about whether they were harmful. I wouldn´t
worry too much there, but...
Actually, I was mainly trying to be sarcastic - although I do know
that some now claim that the ultrasound used for medical purposes may
actually be quite harmful.
I just think it's weird, and slightly annoying, how some people here
seem to be obsessed with this ultrasonic thing. Don't get me wrong, if
you think that Pentax ought to make quieter (or faster) AF, then I
follow you, although it doesn't really matter a lot to me - but
implying that Pentax makes inferior cameras because they don't call
their AF system "ultrasonic"...
BTW, hasn't Pentax made the AF quiet*er*? I haven't really taken much
notice... But I think it would be in their tradition to just release
something a lot better in that respect as just the next generation of
their system and a result of continual improvement, rather than a new
"feature" they make a lot of fuzz about. And I prefer the Pentax way,
there...
- T
DagT
Den 4. okt. 2005 kl. 01.51 skrev Herb Chong:
pick up and use one of those bodies for a little while and you will
know what those terms translate into in real images. AF on any of
the Pentax bodies is much louder compared to their competition.
most of the time, it is irrelevant in terms of image contents, but
if the AF noise happens to distract the subject, then it matters.
Herb....
