Sonic range of Nikon autofocus lenses?

[trothwell]

<p>According to this website:<br>

http://cpn.canon-europe.com/content/education/technical/usmlens_technology.do<br>

Canon USM lenses operate around a range of 30,000Hz. Does anyone know what the approximate range of Nikon ultrasonic autofocus lenses is? I have not yet been able to enter a search into Google that is turning up the answer.<br>

<br />Thanks!</p>

[Andrew Garrard]

<p>No idea. But "the mosquito" device for repelling children has recently been installed at a car park near my work place, and this proves that I can clearly hear (painfully loud) noises at around 17.4kHz. I can't hear a whine from my Nikon lenses, so I'm guessing it's something in the same ball park as Canon's, or higher.<br />

<br />

Are you worried about startling wildlife? (I don't think my cats tend to react, other than to the lens itself moving, but then they are pretty oblivious to a lot of things, for creatures that are supposed to be known for their reactions.)</p>

[trothwell]

<p>My 18-month-old border collie goes bonkers when I use my Canon SLR camera. I have tracked it down to, she must be able to hear the USM focusing, since her odd behavior starts even when she cannot see the camera. I was hoping perhaps Nikon autofocus operates in a significantly different sonic range...</p>

[lilly_w]

<p>Can't help with the frequency but have to mention an incident I experienced while shooting a wedding (as an invited guest) with a Nikon 80-200/2.8 AFS. I was near the speakers of a wireless-microphone sound system. The AF of the lens interefered with the sound in a <em>very</em> pronounced way...totally disruptive. I resorted to manual-focus and all was well.</p>

[Andrew Garrard]

<p>I just had a google, but did no better. However, Wikipedia points out that it's hard to make ultrasonic motors with very high frequencies because the tolerances are small (the wave displacement decreases as frequency increases). On that very tenuous basis, I'd be surprised if the Nikon solution is more than a factor of two different from Canon's, though the companies are, I'm sure, ducking each others' patents and will have some differences.</p>

[nick_baker]

<p>I have sometimes noticed butterflies seem to get spooked by AFS on the 105VR and 300F4. Only sometimes, so either it is particular insects that are affected, or the noise varies according to circumstances.</p>

[pete_s.]

<p>My google fu is strong today :-)<br /> US patent 5,376,855 - Driving device for ultrasonic wave motor by Nikon shows a figure on page 17 (figure 18) drive frequency between 20-23 kHz.</p>

<p>The obvious solution is of course to use regular AF and AF-D lenses that uses the dc motor in the camera body and has no ultrasonic tendencies. That's an option all Nikon shooters have. Well...at least those that have enthusiast cameras like D70/D80/D90/D7000 or any of the prosumer or pro models.</p>

<p>Another solution is to add a split image focusing screen to the camera and use manual focus lenses. Either cheaper older lenses from Nikon or super high quality lenses from Zeiss and others. Nikon D7000 or higher will work fine with any manual focus lens from the 70's or newer.</p>

<p> </p>

[Andrew Garrard]

<p>Well done, Pete. I did try hunting for patents, but may have scuppered myself by trying to use "SWM" (which, now I think about it, would be a retrospective branding). Of course, you don't have to use a split image screen - you can always use live view.<br />

<br />

There are blimps/mufflers that are used to muffle SLR noises in quiet environments. They mostly worry about hiding the mirror clatter, but they'll muffle the lens noise to some extent as well - probably better at high frequencies than at low ones. Perhaps this would be an option? I'd not be surprised if you'd get some benefit out of getting a sheet of acoustic cladding for silencing PCs and making a tube out of it which can fit over a lens.<br />

<br />

I believe some third party solutions (Tamron?) use appreciably different technology to get the same effect. They might manage different frequencies.</p>

[rodeo_joe1]

<blockquote>

<p>"The obvious solution is of course to use regular AF and AF-D lenses that uses the dc motor in the camera body and has no ultrasonic tendencies. That's an option all Nikon shooters have."</p>

</blockquote>

<p>That last statement is a bit misleading to a Canon user that may not be familiar with the variation in Nikon's camera bodies. <em>Some</em> of Nikon's cameras are able to use older AF and AF-D lenses that only have "screwdriver" type AF coupling, as well as AF-S lenses. Whereas some of the lower-end Nikons can only AF with lenses that have a built-in motor - either normal or ultrasonic.</p>

<p>In other words, not <em>all</em> Nikon shooters have the option to use regular AF and AF-D lenses. Not without sacrificing their AF ability.</p>

[trothwell]

<p>Thank you everyone!<br>

Pete, that was exactly the info I was seeking. Assuming my original link about Canon is correct, I would say Nikon's system might be different enough to make it worth a try.<br>

I tried seeing if my dog would respond to one of those ultrasonic training devices, and she did not seem to notice it at all. Those (from what I can tell) emit a tone around 20kHz, closer to Nikon's alleged autofocus system than Canon's.</p>

[sem_svizec]

<p>I guess a dog that can hear 30 kHz can surely hear 20 kHz too. There may be a difference in the sound pattern and volume - like the difference between a flute and a drill, for example. Ask a Nikon shooter for a quick experiment... <br>

If you want to hear this yourself, you need a high-frequency microphone and recording device, then play back recordings with a reduced frequency. Bat researchers do it all the time ;)<br>

http://socialsounddesign.com/questions/2359/re-recording-ultrasonic-frequencies</p>