| Author | Thread |
|
|
05/02/2007 02:23:05 AM · #1 |
or operator error? ;)
I have noticed with some recent photo shoots that my Tamron 28-75 appears to focus 6-12' in front of where AF locks. These pictures are from a tripod mounted session. f8, 1/160, ISO200. If you look closely at crop1 the the area in focus appears to be the grass in front of the girl's feet. I used manual focus to focus the lens and checked the AF on an area of high edge contrast. (@ the edge of the wife's hair and the husband's white shirt) I also included crop2 to show two of the faces close-up. I did not run USM on these samples.
Crop1 
Crop2 
Full shot 
Am I pixel peeping? Am I hallucinating? The problem concerned me so much that I rented a 24-70L for a wedding a couple of weeks ago to be safe. The lens was a dream and the results were excellent. Here is a sample crop with the 'L' lens. No USM applied.
I have had plenty of pics with the Tamron which I felt were ultra-sharp. At first I figured using it at f2.8- f4.5 was the problem. Now I'm not so sure. Anyone with experience/suggestions/opinions?
Thanks, |
|
|
|
05/02/2007 02:34:19 AM · #2 |
It does look softer than I would expect, but can't tell where the actual focus is. I know someone on here created a test to figure out if their lens was focusing incorrectly. From what I can remember it had something to do with laying out a tape measurer and focusing on that and then to see where the focus ends up. I don't remember how they made sure that it focused exactly right, but if it is off quite abit, you should be able to tell. Maybe whoever it was will show up eventually, or someone else will know. Is it under warranty? maybe you can send it in. Hope this marginally helps. :)
Joe
|
|
|
|
05/02/2007 02:45:22 AM · #3 |
The tape sounds like a good idea. Might be able to pin down if actual focus is in front of the AF point. Need to check my warranty. Its only about 14 months old.
Thanks,
Nice signature BTW. I need to get mine updated. Been laying a little low during the WPL break. |
|
|
|
05/02/2007 03:02:46 AM · #4 |
Originally posted by mpeters:
The tape sounds like a good idea. Might be able to pin down if actual focus is in front of the AF point. Need to check my warranty. Its only about 14 months old.
Thanks,
Nice signature BTW. I need to get mine updated. Been laying a little low during the WPL break. |
Me too, but I needed an update button so it brought me back. The new season sign ups should be in about a week. :)
|
|
|
|
05/06/2007 10:39:18 PM · #5 |
| Mark in this thread are some links to some focus tests that might be useful. And don't forget to sign up for DPL :) |
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2026 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 01/01/2026 09:48:42 AM EST.
