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Old Feb 23, 2010, 9:32 PM   #11
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the first image though since i focused on the treeline - surely even if was fron focusing the foreground would at least be in focus but nothing in the image is sharp at all
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Old Feb 23, 2010, 9:55 PM   #12
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ok i just fired off a few shots of my computer keyboard and for the life of me i dont understand but the images are sharp with no trace of front or back focus will have to try it out again tomorrow outside on some moderately distant objects but i bought this lens for landscape shots not close up so unless i can work out how to get an acceptable shot from it will have to do something about it - not the most expensive lens i have but its not far off so it needs to work
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Old Feb 24, 2010, 2:49 AM   #13
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John, I was looking at a lense on "CameraLabs", where it specifically throws the background OUT OF FOCUS... I am wondering if your lense does the same if it is not at something like f 16 or f 22... I don't know, but the CameraLabs video presentation later made me think of your situation. Please try again, and if you would, do an aperature experiment of sorts... Your problem is important to all of us, though I know it must be really troublesome for you, to say the least.

Mtngal had some interesting points... perhaps your focusing points, not just aperature, are important to consider.

All the best.

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Old Feb 24, 2010, 10:00 AM   #14
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On a quick read of this thread I didn't see this mentined: I don't know if this matters with mirror lockup, but you were using a tripod - did you remember to turn off the SR?
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Old Feb 24, 2010, 10:30 AM   #15
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Good point! Uggg... I read of that! Good point, penolta.
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Old Feb 24, 2010, 1:23 PM   #16
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Hey JP,
Like Harriet, I too has a focusing issue with my 12-24 so, I'd recommend checking that out first. However I also notice I have less DOF than I think I should at times. I do think I'm getting much better shots since I adjusted the focus setting.
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Old Feb 24, 2010, 2:15 PM   #17
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Keyboards make lousy focus charts - it's easy for the camera to be actually focusing on the row below and you wouldn't see the ff. Download a focus chart that has either very light greys around the focus line, or else nothing in the center. And be absolutely square to the chart or you'll get differences between left and right sides of the chart. The camera's focus center is quite a bit bigger than the indicator in the viewfinder - it was interesting to play with the chart I printed - http://regex.info/blog/photo-tech/focus-chart . I think I printed the 10% grey version - it was light enough that the camera couldn't focus on it (test it first). The lens is so wide, it's harder to get accurate pictures than you would with a longer lens.

The other thing is that I keep my aperture fairly large - it's sharper from f4 thru f11. Any smaller and the image quality isn't as good.
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Old Feb 24, 2010, 2:30 PM   #18
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Quote:
Originally Posted by penolta View Post
On a quick read of this thread I didn't see this mentined: I don't know if this matters with mirror lockup, but you were using a tripod - did you remember to turn off the SR?
i used the 2 sec timer which gives automatic mirror lock up and turns sr off - so not that

will try printing out a proper focus chart giving that a shot too
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Old Feb 24, 2010, 2:30 PM   #19
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On a ultra wide angle lens such as a 12-24, DoF should accomodate most focusing issues. I'd have the lens checked...there could be an alignment/ calibration issue.

I have experience using a 12-24mm f/4--images are tack sharp at most f/stops (some distortion at the edges at 12 mm especially at the f/stop extremes, but that is not uncommon). I get a lot of use out of the lens for landscape as well as inside family pictures.
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