Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
06-11-2010, 10:40 AM   #1
Senior Member
bluebronco's Avatar

Join Date: Feb 2008
Location: Iowa
Photos: Gallery | Albums
Posts: 170
Loud Auto Focus K20 Pentax 50mm Macro

I love my Pentax gear. My first was a K1000 film camera.

I really haven't even played around with Nikon or Cannon. I was at BestBuy the other day and I decided to look. I played around with about 5 of the cameras. I was amazed at how quite they were compared to my K20 with 50mm 2.8f Macro. At first, I didn't even realize that they were focusing. So quite. So hear it is.... why is the Pentax so loud?

06-11-2010, 10:51 AM   #2
Site Supporter
ismaelg's Avatar

Join Date: Apr 2009
Location: Puerto Rico
Photos: Gallery
Posts: 962
Do you know if you were testing ultrasonic lenses?
They are much quieter than traditional AF. In Pentax that is SDM.

06-11-2010, 11:52 AM   #3
Veteran Member

Join Date: May 2009
Location: Twin Cities, MN
Posts: 2,869
Two things - even most of the cheap canon and nikons have some sort of ultrsonic motor now. Compared to the screwdrive lenses (including the macro, but not SDM which is quiet) they are much quieter. Secondly, Macro lenses have much more focus travel since that is an inherent design for a macro lens - the elements move much farther away from the film/sensor plane as you get closer to the subject (which 50mm macro version do you have - is the DFA an internal focus lens? my Pentax-F macro extends close to 2 inches beyond the lens barrel - and yes, it is easily my loudest lens!)
06-11-2010, 12:31 PM   #4
philbaum's Avatar

Join Date: Oct 2007
Location: Port Townsend, Washington State, USA
Posts: 3,659
Pentax's SDM is usually very quiet, at least the 2 lenses i have with it. At first i wasn't even sure the DA-300 was focusing until you see the image coming clear in the viewfinder.

But without the screwdrive and motor in the body, we wouldn't have the ability to use the older lenses that require screwdrive. And, it might not be so easy to engineer really small pancake lenses with an electrical motor embedded in the lens frame. (i'm not so sure about this last statement) So it appears that Pentax bodies may have to maintain screw and SDM drives for some time to come.

I'm not sure, but i doubt that the micro 4/3s cameras and the Sony NX camera have sonic motors in their lenses.


  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
50mm, camera, dslr, k20, macro, pentax, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
pentax kx shaking noise loud loud ? ritualart Troubleshooting and Beginner Help 15 08-12-2010 08:41 AM
Auto Focus speed - K200 vs K20 Enc0der Pentax DSLR Discussion 0 03-27-2009 05:36 AM

All times are GMT -7. The time now is 10:15 AM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]