Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-29-2018, 12:26 PM   #1
Veteran Member




Join Date: Apr 2012
Posts: 372
AF hard stopping on DSLR

I got couple film lenses to play with my K3, namely the Tamron 28-200, the FA 80-320 and the FA 28-90 or 24-90 I forgot. I found they have something in common, they all have AF hard stopping, the motor stops like hitting the wall, unlike my non SDM 55-300 that stops smoothly. Since I don't have a AF film camera to test I can't tell how the lenses actually perform on a body they designed for, or hard stopping was how old AF lenses work ?

12-29-2018, 12:32 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 48,223
The motor on the K-3 (and newer models) is more powerful than those on film cameras, so the hard stop effect feels more pronounced. Newer lenses sure are nice in that they don't have such behavior.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

12-29-2018, 12:47 PM   #3
Veteran Member




Join Date: Apr 2012
Posts: 372
Original Poster
I think you are probably right, I can feel the torque of the motor when I grab the focus ring by mistake during AF.
12-29-2018, 01:03 PM   #4
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North-East England
Posts: 11,874
It's also worth bearing in mind that most film era lenses have a hard infinity stop, whereas modern AF lenses tend to go past infinity and have drive mechanisms which simply "slip" when the end of travel is reached. Plus, I suspect the gearing in those older film lenses has less reduction.

12-29-2018, 03:29 PM   #5
Site Supporter
Site Supporter




Join Date: Nov 2015
Photos: Albums
Posts: 1,005
Short answer: they slam around on film cameras, too

-Eric
12-29-2018, 06:30 PM   #6
Veteran Member




Join Date: Apr 2012
Posts: 372
Original Poster
Talking about gear reduction I found my 2 film lenses work quite differently, the Tamron 28-200 which is macro capable has a very short focus throw not so MF friendly, but the FA 80-320 has a quite far MOD of 1.4m has near a full turn this is weird design.
Reply

Bookmarks
  • 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!
af, fa, film, k-mount, lenses, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Merry Christmas. Just stopping by 80turbota Pentax Film SLR Discussion 5 12-28-2017 06:04 AM
Strange aperture bounce with Pentax-M 50mm f/1.4 (not the usual stopping down fault) callumross Pentax SLR Lens Discussion 5 12-20-2017 11:05 AM
For Sale - Sold: Paul C. Buff Einstein 640 monolight strobe - Action stopping wonder! Edgar_in_Indy Sold Items 6 05-26-2017 03:52 AM
Time Lapse Interval Random stopping following.eric Pentax K-30 & K-50 7 03-31-2017 10:10 AM
Any Hard Body Holsters out there (Think Tank? Lowe? anything hard?) cadmus Pentax Camera and Field Accessories 16 03-05-2011 08:25 PM



All times are GMT -7. The time now is 05:45 PM. | See also: NikonForums.com, CanonForums.com 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?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top