Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-31-2009, 05:49 PM   #91
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Class A Quote
Your validation by testing does not provide a reliable answer either because I highly doubt that your testing methods lead to repeatable results in a precise manner (you called them "haphazard testing methods" yourself ).
Obviously. My goal isn't to literally *measure* the error, but just get a rough idea of how problematic it is.

QuoteQuote:
I find it impressive that you can easily fix recomposition focus errors by using manual focus. With a stock focussing screen, which "lies" at such critical apertures, I personally don't stand a chance of accomplishing this.
Well, I use manual focus lenses a lot, so I've learned to predict pretty well what is going to happen to my focus zone with regard to the focus-screen-lying issue. But I'll admit to some trial-and-error as part of my methodology!

08-01-2009, 03:10 AM   #92
Junior Member




Join Date: Apr 2008
Location: Prague
Posts: 42
QuoteOriginally posted by HeavyD Quote
I recently bought a new open boxed K10d and a Sigma 17-70mm f/2.8-4.5 lens with a Hoya Pro1 UV filter. I was having the same focus issue with the Sigma as you are. ... The Sigma is out of focus while the Pentax is perfect.


Sigma 17-70mm

This looks like typical motion blure, not soft lens. But since you are using tripod, the problem can be with Sigma's chip - if the lens tells the body incorrect focal length, the SR can cause similar effect. Can you repeat the test without SR ? Or can you analyze EXIF data for some suspicious values ?
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, ev, f/4, focus, image, iso, length, lens, pattern, photography, sec, tamron
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sharper images--auto or manual focus Dimeman Photographic Technique 10 02-05-2010 11:01 AM
OK, Which is Sharper ? wll Pentax SLR Lens Discussion 10 09-06-2009 06:27 PM
Tweaking the K20D for Sharper Images nanhi Pentax DSLR Discussion 58 06-19-2009 12:18 AM
Shouldn't this be sharper? FHPhotographer Pentax SLR Lens Discussion 17 01-17-2009 07:20 PM
What is sharper karq Pentax SLR Lens Discussion 6 10-25-2008 02:17 AM



All times are GMT -7. The time now is 05:38 PM. | See also: NikonForums.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