Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-30-2008, 07:53 PM   #1
Junior Member




Join Date: Apr 2008
Location: Adelaide, Australia
Posts: 29
Flash Pictures OOF Mystery

I posted this thread on the dpreview forum over a year ago but never got a positive confirmation so I will try it here again.

The equipment in question is K10D + Sigma 17-70mm + Pentax AF-540FGZ flash. I find that whenever I use flash in dim places and the red light on the flash fired to assist focusing, the pictures will turn out to be out-of-focus, particularly at the wide angle end. This does not happen with the built-in flash nor with my other Pentax lenses. I borrowed a Sigma 18-125mm from someone and repeated the test and it behaved in exactly the same manner. My conclusion is Sigma lenses may not be 100% compatible.

I am wondering if anyone share similar experience.

David

04-30-2008, 08:02 PM   #2
Senior Member
joefru's Avatar

Join Date: Mar 2008
Location: South Louisiana
Photos: Gallery
Posts: 210
When the AF assist is active, how does the AF speed compare to when it's not? You say "turn out to be," so does that mean that you don't notice until you look at them on a computer, or is the OOF-ness really noticable?
04-30-2008, 10:00 PM   #3
Junior Member




Join Date: Apr 2008
Location: Adelaide, Australia
Posts: 29
Original Poster
The OOF is immediately apparent on the LCD when magnified to 4x. It is grossly OOF, not just a tiny bit. I actually ran a test to examine the change in focus on the distance scale, the focus consistenly falls behind the subject by about 0.5m whenever the AF beam fires. In terms of AF speed, I would say it is roughly the same as if it was focusing in a dim environment without AF beam firing, in other words, slooo...w.
04-30-2008, 10:53 PM   #4
Veteran Member




Join Date: Sep 2006
Photos: Gallery
Posts: 5,713
David,
Contact Sigma USA here's the link

To me is sounds like a problem with the lens. And if I remember correctly they usually just re-calibrate them, occasionally changing a chip or something.

Sigma USA is really good at the moment, and usually have their warranty repairs done within 2 weeks or so

Please note that I can't promise you your lens back in 2 weeks, there's just a good chance of it.

04-30-2008, 10:54 PM   #5
Site Supporter
AlexM's Avatar

Join Date: Mar 2008
Location: West Covina, CA USA
Photos: Gallery
Posts: 162
Are you spot focusing or using patterned?
04-30-2008, 11:19 PM   #6
Junior Member




Join Date: Apr 2008
Location: Adelaide, Australia
Posts: 29
Original Poster
I used AF-S mode and select the centre AF point.

And btw I live in Australia so I can't send the lens to Sigma US.
05-01-2008, 12:30 AM   #7
Veteran Member




Join Date: Sep 2006
Photos: Gallery
Posts: 5,713
Sorry about that David, Dyslexia gets the best of me again

It's almost looking to me like CR Kennedy is your Sigma distributer there, so I imagine that they're the one's you'll have to contact.

Here's their link.

Sorry, I don't know how their service record is

Good luck with it.
05-01-2008, 12:55 AM   #8
Junior Member




Join Date: Apr 2008
Location: Adelaide, Australia
Posts: 29
Original Poster
Can someone who owns a K10D with any Sigma lens (17-70mm is desirable) and a Pentax AF360/540FGZ flash run a test for me tonight in the dark and tell me what your experience is?

I am keen to eliminate the possibility that my K10D body or flash is screwing up the focusing.

David

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!
camera, dslr, flash, lenses, pentax, photography, pictures, sigma
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Nature Oof, oof, oof KarenH Post Your Photos! 7 10-30-2010 01:36 AM
Abstract OOF Rense Post Your Photos! 3 08-31-2010 06:35 PM
OOF , lens or camera ? Squier Pentax DSLR Discussion 22 05-08-2009 10:11 AM
K10D Soft or OOF? innershell Pentax DSLR Discussion 20 07-23-2008 11:41 AM
OOF & nothing but the OOF! Akcelik Pentax DSLR Discussion 38 03-10-2007 09:53 PM



All times are GMT -7. The time now is 08:40 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