Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-27-2009, 01:41 AM   #31
Veteran Member
netuser's Avatar

Join Date: Oct 2008
Location: Azores Islands, Portugal
Photos: Gallery
Posts: 2,241
QuoteOriginally posted by philbaum Quote
netuser,
That's really odd. I assume that when you put other autofocus lenses on the K20d, they work fine. Which sort of says that the AF circuit on the K20d is fine???

Have you installed the lastest ver 1.3 firmware on the camera?

Do you have different batteries in K200 vice the K20 (of course, i just remembered the K200D has aa batteries) This kind of implies that battery voltage is making a difference. Try a freshly recharged battery in your K20D, or perhaps a different one.

Also, in an old thread on dpreview, there was a discussion on the DA 50-135/16-50 about how a coupla guys fixed their SDM problems by just cycling their AF circuits by focusing on something close, then something far away, and then repeating it several times. Apparently the problem got less and less and then went away.

Regards my only SDM lens, the DA*300, i've not had any problems wtih the SDM AF. It was bought in 2008 in the fall and is working fine. No hangups ever. I just focused on a brick wall in shade inside my house but sunny outside. It focused fine and locked all the way to aperture F22 at 0.7" shutter in AV, AFS. I tried at each aperture
Yes, using other non sdm lenses on k20 autofocus is FAST and reliable, no hunting.
Just now I was trying again with DA18-250, really fast always locking on the target and no hunting at all changing from focusing in infinity to 5 meters away etc.
Same testing with the DA*300 and problems occur specially when changing distances, for instance infinity to 5 meters away or the other way around, hunting a lot. Pressing AF button it spins looking for focus until it stops and nothing. I have to press again to restart the spin looking for focus until it gets it.
If I lock on a target at a specific distance and then go for other targets at more or less same distance it locks faster with no hunting (using AF-C)

On k200d, for now sdm is working properly and I already use different brands of rechargeable batteries. I just don't like to use it on k200d due to shooting speed/buffer

I bought DA300 with an extra fee for insurance, meaning I can during the first year of warranty send the lens back and get a refund to use on anything else I want to buy. So I will keep playing with the lens at least until October before I send it back or this sorts out.

07-27-2009, 11:00 AM   #32
Veteran Member
netuser's Avatar

Join Date: Oct 2008
Location: Azores Islands, Portugal
Photos: Gallery
Posts: 2,241
Forgot to say I had firmware 1.3 on k20d but even downgraded to 1.1 and give it a try and back to 1.3 and same thing, no sdm
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!
focus, hsm, k-mount, pentax, pentax lens, sdm, sigma, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Travel Lens Final Decision : Pentax 17-70 SDM Vs Sigma 18-250 HSM Christopher M.W.T Pentax SLR Lens Discussion 34 02-22-2010 10:54 AM
Any 1.4x TC with AF for HSM or SDM tram57 Pentax SLR Lens Discussion 14 02-17-2010 07:35 AM
HSM/SDM lenses for Pentax? azcavalier Pentax SLR Lens Discussion 3 11-04-2007 08:50 PM
Sigma HSM compability with Pentax SDM gawan Pentax SLR Lens Discussion 3 08-02-2007 03:14 PM
Sigma 10-20 mm F/4-5.6 EX DC HSM NOT HSM for Pentax? Chilichoco Pentax SLR Lens Discussion 10 05-24-2007 04:57 PM



All times are GMT -7. The time now is 05:55 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