[fullmental]

I just got a used Pentax DA 18-135mm ED AL DC WR (might have missed an acronym there, but I'm sure you know which one that is), and I was under the assumption that the DC motors were actually silent, since everyone claims they are. Well I worked on a few test shots today and the lens is most certainly not silent! It's quieter than a screwdrive for sure but it is definitely audible when focusing. Is this normal and is "silent" just marketing jargon, or did I possibly receive lens with a worn out/defective AF motor - or is it nothing to worry about? I've never owned/been around one before so I don't know if it's normal or not for them to not be literally silent.

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Last edited by fullmental; 12-22-2015 at 12:27 AM. Reason: speling

[Digitalis]

It's quieter than a screwdrive for sure but it is definitely audible when focusing.

Even sigma lenses equipped with HSM make some noise when focusing, I can only assume DC and SDM lenses do as well.. I suppose it depends on how much noise is considered" intrusive". Your proximity to the camera itself make things audible that others probably wouldn't notice.

[Adam]

It's a faint hum, but certainly audible when you're holding the camera. Your subject probably won't hear it, though.

Here's what the lens is supposed to sound like (start at 23s):

You Tube

You Tube

[Davidparis]

I just got a used Pentax DA 18-135mm ED AL DC WR (might have missed an acronym there, but I'm sure you know which one that is), and I was under the assumption that the DC motors were actually silent, since everyone claims they are. Well I worked on a few test shots today and the lens is most certainly not silent! It's quieter than a screwdrive for sure but it is definitely audible when focusing. Is this normal and is "silent" just marketing jargon, or did I possibly receive lens with a worn out/defective AF motor - or is it nothing to worry about? I've never owned/been around one before so I don't know if it's normal or not for them to not be literally silent.

There is no such lens which will meet your apparent expectations. Morbid, pin-drop silence in a lens except perhaps in the very best manual lenses simply do not grace the face of the Earth. A Pentax DC-motor lens's noise as compared to a Pentax screwdrive is vastly superior in noise level, accuracy, rapidity and general satisfaction. Can't tell if your 18-135 has a problem, but adjusting expectations from dead or near silent to "enormous improvement" over screwdrives would put things in better perspective. The DC-equipped lenses definitely hum and purr briefly before AF lock-on, it's quick, it sounds right and it's reassuring.
If you could find a Pentax retailer to whom you could show/demo the lens, he's be able to confirm if there's a problem or not.

[fullmental]

There is no such lens which will meet your apparent expectations. Morbid, pin-drop silence in a lens except perhaps in the very best manual lenses simply do not grace the face of the Earth. A Pentax DC-motor lens's noise as compared to a Pentax screwdrive is vastly superior in noise level, accuracy, rapidity and general satisfaction. Can't tell if your 18-135 has a problem, but adjusting expectations from dead or near silent to "enormous improvement" over screwdrives would put things in better perspective. The DC-equipped lenses definitely hum and purr briefly before AF lock-on, it's quick, it sounds right and it's reassuring.
If you could find a Pentax retailer to whom you could show/demo the lens, he's be able to confirm if there's a problem or not.

Well, naturally if everyone and their mother says "It's silent" I would assume that means in the literal sense and furthermore that any absence of silence (noise) would mean something has gone wrong. Guess we all know what assumptions make of us . Anyway I'm not concerned if it makes an acceptable amount of noise or not, I just want to make sure I quickly contact the seller for a refund/exchange within the return period rather than assume (there's that word again) that it's normal only to find it's not the case and I wind up with a $300 paperweight.

Anyway, @Adam I can't really hear much in the video you linked with all the background noise, so I recorded my own camera for a few seconds, figure it's easier for someone else to hear it and tell me that's what they hear than to try and describe it. Here's a quick audio clip, first few seconds is a SMC Pentax-F 35-70mm (older, loud AF), followed by the 18-135mm WR, then followed by a camera shutter noise from the K50 for good measure to use as a baseline. Mic was about 6 inches from the camera body and tuned just low enough to not have significant background noise. If there's no troubling volume or other noises in it then great I won't have to worry about it, but better safe then sorry!

[Adam]

Your lens is fine

[fullmental]

Your lens is fine

Marketing jargon strikes again! Okay then, glad that is cleared up. Thanks for the confirmation.

[Davidparis]

Marketing jargon strikes again! Okay then, glad that is cleared up. Thanks for the confirmation.

Good to "hear" that the lens is fine. I think we've defined silent as being a relative term to describe the difference between the DC lenses and the embarassingly loud and obscene sound of the screwdrives. Or perhaps a Pentaxians's silence is a another man's noise...

[TER-OR]

Yeah, you can hear it, mostly because you're holding it inches from your ears and often in contact with your face...

It is pretty quiet, though, and very pleasant to use.

[normhead]

I've been asked to change lenses at bird feeding stations because my 70-210 was scaring the birds, never with the 18-135 or 60-250, thars the difference for me.

[boriscleto]

I've been asked to change lenses at bird feeding stations because my 70-210 was scaring the birds, never with the 18-135 or 60-250, thars the difference for me.

Have you ever asked anyone at a feeding station to not use their machine gun Canikon?

I've only ever had one animal disturbed by the screw drive.

This horse on an Amish farm was upset by the sound of the 18-55 trying to focus in live view on the K-x.

[normhead]

Have you ever asked anyone at a feeding station to not use their machine gun Canikon?

No, but that doesn't mean they haven't been, just not by me. At my own feeder, I've noticed the birds do get used to shutters. I used the K20D the other day just on a whim, and had to switch back, it totally spooked them, (and focuses really slow, and has a burst rates slow it's not really fair to call it a "burst," at my own feeder the birds are used to screw drive,

I guess thats a sure sign there are more crazy Canon burst shooters than there are Pentax screw drive shooters.

[stevebrot]

So how "silent" are the DC motors supposed to be?

How good are your ears? Even linear ring motors whine.


Steve

[nanhi]

Fullmental Sir, certainly my 18-135 WR is not even one-fourth as loud as the video shown by Adam.
Possibly I am too busy taking pictures and cannot hear the noise the DC Motor makes, but honestly I have to literally put the lens to my ears to hear it.
In fact sometimes I double check to make sure the focusing mechanism has moved at all - I will defocus the lens by pointing it at my palms and then focus again. Such is my idiosyncrasy after using screw drive auto focus.
Honestly the 18-135 WR I got with the K-5 brand new from Henrys of Toronto, Canada is pretty silent. In fact very silent.

You say your copy is used. So DC motors can make some noise in case there is binding in the cams, gears and sliding lens barrels. Or the lens has had jars / bangs in use by the earlier owner.
Also my copy is brutally sharp - so much so ladies hate the pimples, skin blemishes or bleached facial hairs on their face. I just chuckle and have a laugh.

[Davidparis]

Also my copy is brutally sharp - so much so ladies hate the pimples, skin blemishes or bleached facial hairs on their face. I just chuckle and have a laugh.

That was an epic comment!