Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-18-2007, 11:54 AM   #1
Senior Member
button's Avatar

Join Date: Feb 2007
Location: Nashville, TN
Posts: 241
Is it possible to improve AF with screw driven lenses?

I can't praise the quality of the original limited lens line enough- oil painting with light is the best I can do. I know (from reading the k10d engineer interview awhile ago) that the k10d's increased voltage (7.2v, I believe) sped up the screw drive considerably vs the AA battery powered cameras. In my opinion, the main thing hampering the original limited line at this point is the "hunting" that occurs to lock focus. I haven't used the new limiteds, and I hear that they are faster. Does anyone know (maybe those of you who have played with the prototypes, if you're allowed to say) if this "hunting" can be eliminated?

John

12-18-2007, 11:59 AM   #2
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,549
QuoteOriginally posted by button Quote
I can't praise the quality of the original limited lens line enough- oil painting with light is the best I can do. I know (from reading the k10d engineer interview awhile ago) that the k10d's increased voltage (7.2v, I believe) sped up the screw drive considerably vs the AA battery powered cameras. In my opinion, the main thing hampering the original limited line at this point is the "hunting" that occurs to lock focus. I haven't used the new limiteds, and I hear that they are faster. Does anyone know (maybe those of you who have played with the prototypes, if you're allowed to say) if this "hunting" can be eliminated?

John
I'm not sure about "eliminate", but switching to a single focus point can reduce it quite a bit.
12-18-2007, 01:55 PM   #3
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
Hunting is because the focus point does not have the correct variations in contrast to establish a focusing point. That is all to do with the image, light available, and lens maximum apature, and nothing to do with the screw drive.

Changing the voltage for the drive will accomplish nothing if the issue is hunting, except faster hunting but no improvement on focus.
12-18-2007, 02:45 PM   #4
Pentaxian
Moderator Emeritus




Join Date: May 2007
Location: Edmonton Alberta, Canada
Photos: Gallery | Albums
Posts: 10,648
AS Lowell and Canada_Rockies have said it is also using the center point and finding a higher contrast part of the picture. If the light is low I always look to find a point of higher contrast to allow the camera to focus. It always works and focuses quickly for me in most situations.

12-18-2007, 04:45 PM   #5
Senior Member
button's Avatar

Join Date: Feb 2007
Location: Nashville, TN
Posts: 241
Original Poster
I probably shouldn't have used the word "hunting." I am referring to the last little bit of micro gyration that the camera/lens combo performs before confirming AF. Phonetically, it goes something like this: zooop, tic, tic, beep (if your AF confirm beep is set to "on" ). I don't mind the initial AF speed ("zooop"). I'd like to see that last little movement disappear ("tic, tic"), which basically doubles the AF time.

John
12-18-2007, 06:47 PM   #6
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by button Quote
I probably shouldn't have used the word "hunting." I am referring to the last little bit of micro gyration that the camera/lens combo performs before confirming AF. Phonetically, it goes something like this: zooop, tic, tic, beep (if your AF confirm beep is set to "on" ). I don't mind the initial AF speed ("zooop"). I'd like to see that last little movement disappear ("tic, tic"), which basically doubles the AF time.

John
What you may be hearing is the camera changing focus as you move, assuming you are in continuous mode. Remember you usually can't hold perfectly still, and most subjects are not flat, therefore if you move the lens, the focus point probably shifts a little. Try the same on a tripod. I hear this from time to time, usually shooting through branches
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!
k-mount, line, pentax lens, screw, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
screw mount lenses MitchellScott Troubleshooting and Beginner Help 13 05-24-2010 12:39 PM
LBA is driven by Pentax fans? braver Pentax SLR Lens Discussion 7 03-02-2010 02:58 PM
SCREW interchangeable lenses... cheekygeek Pentax Film SLR Discussion 11 02-13-2010 12:35 PM
Screw Mount lenses on my PZ-10 eccs19 Pentax Film SLR Discussion 1 10-28-2009 08:28 AM
screw mount lenses jbrowning Pentax SLR Lens Discussion 42 06-21-2008 10:02 AM



All times are GMT -7. The time now is 03:59 AM. | 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