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08-09-2010, 03:35 PM   #1
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New DA 16-45mm Distortion?

Just took a few test shots with my new lens, and the few shots at 16mm seem to be very blurry in the upper right of the frame. It's really obvious in the trees. Everywhere else in the frame looks fine. Is this operator error? I am a novice after all. Is there a better way to test the lens and not the photographer?

Here's a link to the jpg, raw is similar. K20, 1/250, f6.7, 16mm, ISO100

http://www.scorpion-bowl.com/WebHost/Public/IMGP4742.JPG

Here's a resize, although not very useful...

Thanks,
Gary

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08-09-2010, 03:38 PM   #2
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Take a shot of a brick wall.
08-09-2010, 03:39 PM   #3
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Hi Gary,

Ultra-wide lenses do have a tendency to do that. The effect can be minimized by shooting around 18mm, or by using a smaller aperture.

Adam
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08-09-2010, 03:45 PM   #4
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Adam, are you sure? It's only the right corner/right side. The left hand side is unaffected. It looks like motion blur to me. Chances are when he pressed the shutter release he tilted the camera's right side.

A brick wall test should prove conclusive.

08-09-2010, 04:57 PM   #5
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Thanks for the replies...

I was on a tripod, probably not mirror-up. I'll look for a good brick wall.
08-09-2010, 05:48 PM   #6
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QuoteOriginally posted by scorpionbowl Quote
Thanks for the replies...

I was on a tripod, probably not mirror-up. I'll look for a good brick wall.
Or print out a AF Test chart and shoot that.
08-10-2010, 07:01 AM   #7
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"The effect can be minimized by shooting around 18mm, or by using a smaller aperture."

Aperture has absolutely no effect on the distortion present in a lens If your lens has got it...you live with it, or get software to correct it. Adobe lens correction tool is useful but for a more comprehensive approach use PT lens or DxO Optics raw development suite.
08-10-2010, 07:40 AM   #8
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+1 for take it just off 16 mm, even 17 mm or 18 mm makes a difference, shoot at f8 to f9.5 if quality is your prime concern.

Don't spend too much time pixel peeping at the corners - unless you are printing really big!

08-10-2010, 08:14 AM   #9
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Sorry, you can't judge the 16-45 with this photo. First of all, there's too much depth of field for everything to be in focus at f6.7. It looks like your focus was on the water fairly close to you. You used a tripod but didn't use MLU, which can cause blur. Did you disable shake reduction? You'll need a more controlled test for testing the lens.
08-10-2010, 08:20 AM   #10
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QuoteOriginally posted by Digitalis Quote
"The effect can be minimized by shooting around 18mm, or by using a smaller aperture."

Aperture has absolutely no effect on the distortion present in a lens If your lens has got it...you live with it, or get software to correct it. Adobe lens correction tool is useful but for a more comprehensive approach use PT lens or DxO Optics raw development suite.
The original poster referenced distortion, but his complaint has nothing to do with lens (barrel) distortion. He's concernced about blur in the top right corner, a completely different issue than distortion.

No doubt there is some distortion, but it does not impact negatively on this photo, and it's not the reason for the original post, nor for Adam's response (which I agree with, BTW).
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