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Old Oct 21, 2007, 4:12 PM   #1
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Hi all,

First post on the forum - For 8 months I have been gushing over my D40 and 18-200 VRII but today when I really needed it, it seems to have let me down. I took pictures for a group outside on an overcast day, and the white parts of clothes had a serious white halo around them. It looks like crap. I had it set on Auto, picture size large, norm.Attached is about a 15% crop from it (then reduced) from the right side of the picture (seemed to be a little worse near the edge of the picture). The picture was taken at F5, 1/100, 32mm. Any explanations why this is like this? Thanks.

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Old Oct 21, 2007, 4:39 PM   #2
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I'm seeing some chromatic aberrations in the form of purple fringing at high contrast transitions (the white clothing in particular). That's pretty common with this type of lens ("all in one" type lenses with a big difference between widest and longest zoom setting). But, even very good lenses can have it in some conditions and your Nikkor 18-200mm is one of the better lenses in class (with that type of range from wide to long).

Stopping down the aperture more from wide open (use a smaller aperture, represented by a higher f/stop number) would probably help. Your Depth of Field was relatively shallow for that shot at f/5 (and the closer subject on the right was a tad out of focus, contributing to some of the fringing).

You're too close to the widest available aperture (that was shot at f/5), and most lenses are sharper a couple of stops down from wide open (try around f/8 and that will probably clear up some of it, giving you a bit more depth of field at the same time).

If you have any filters on the lens, you may want to try and remove them in case they're contributing to optical degradation.

That image also has some "blown highlights" (slightly overexposed) in some of the white areas, which could also have been a contributing factor. You may want to try using a -EV setting with Exposure Compensation for a slightly darker exposure shooting in a non-Auto mode. For example, P (Programmed Auto) would allow you to control that part more easily.

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Old Oct 22, 2007, 12:20 PM   #3
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So the classic good news-bad news - there's nothing really wrong with my camera but I'm a lousy photographer! I guess I should be relieved!
I was just surprised that it was so bad. I mean hugely noticable. And I haven't seen it before in 8 months of taking pictures. I find it hard to believe that an f-stop or two could remedy it. I wish I would have taken some pictures with the kit 18-55 to compare. I guess I default to the 18-200 because I was hand-held and I love the VR.
I wish I could pin-point the conditions here that are making it so bad.
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