Nikon 18-200 VRII - lack of sharpness at the long end...

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James Cowell
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Back at the start of January I purchased a second-hand Nikon 18-200 VRII from a well known company who advertises here (I've also dealt with them in the past) to pair with a brand new D7100.

I took a few shots to test and was moderately happy (thought there was a lack of sharpness/camera shake when at the long end) but put that down to not ideal light and my lack of experience with the lens.

We've just returned from holiday where it was sunny and I could not get a sharp image at the telephoto end at all, but the wide end was acceptable - has anyone had experience of this with other copies?

I would go back to the vendor, but their T&C's expressly state:

9.6 General exclusions (What's NOT covered):
9.6.4
- faults relating to image sharpness of a lens that is clearly open to human judgement;

I also have a brand new 35mm f1.8 that is tack sharp, so I'm going to rule out a camera issue...
 
Given that sharpness is 'open to human judgement' as you say, it's even more difficult without seeing any images to compare ;)

Having said that, super-zooms are well known for reduced sharpness at the long end, especially around the edges. Fact of life. Best aperture will be around f/11.
 
Yep - tried attaching some pictures but doesn't seem to want to from work, will put some up this evening...
 
You weren't using a UV filter were you? I noticed that when I used mine with a UV filter, the shots were really soft at the longer end.
 
Try a shot with and without the filter, then post up!

The first one simply looks out of focus, but UV filters can confuse AF systems at the long end and certainly do degrade the IQ, but I wouldnt have thought by that much?
 
You might want to try some of the suggestions mentioned here, especially turning the VR off. I knew of a photographer several years ago who had a similar problem ( can't remember what lens it was, but was on a Nikon camera) who had sharpness problems when the VR was turned on. Also you can get some problems with long lenses where you get mirror jar if the shutter speed is too slow.

If you can fit on tripod and turn VR off. Select a shutter speed that is twice that of the focal length. Use an aperture that is at least 2 stops down from wide open. and if you can lock the mirror ( not always possible. Then take your test shots squeezing the shutter as gently as possible. Now have a look at the results. If it is still unsharp, back it off to about 175mm and see if that improves things.
I've a Canon 100-400 and at 400mm it is a little soft. At about 375mm it's fine.

Hope these suggestions help
 
Right, just taken with and without the filter and it does seem to make a difference, but it looks like a focus issue - both were exposed at 1/1600 @ f5.6 and using manual focus (focussed on the first chair) with VR off.

With filter:

View attachment 9713

Without filter:

View attachment 9714

In my eyes, without the filter is sharper?
 
Agreed. But it doesn't show the problems as badly as your original examples, suggesting perhaps the focus was just off?
 
The chairs in the second set of pictures were not as far away as the holiday snaps and potentially the heat haze was partially to blame?

Happy to put it down to user error, but I do have a fair bit of experience :)

Used filters on every lens I've owned (including 'comparable' Nikon 80-200 f2.8 push/pull on a Nikon F4S, Nikon 70-300 AF-S on a D700 and Sony NEX 18-200 on a NEX-7) and all have been pin sharp throughout their ranges.

The main reason moving away from the NEX-7 was the focus speed and hit rate when capturing the kids (especially in low light) and looking around the D7100 has some of the most intelligent focussing currently available on the market - however, it is a new camera to me and I'm not well acquainted with the AF fine tuning setting so will look into it over the weekend...

Thanks to all for the replies!
 
For some reason, I can only see James's shots at a tiny size so can't make any judgements but he does mention heat haze in the holiday shots as well as a certain amount of distance. I would suspect that that could well be a nail on head interface! Not only does heat haze cause waviness but it can also throw focussing off, especially AF. Not a huge amount but enough to spoil shots (got loads of carp shots of Mediterranean landscapes on film!)
 
Phil - I'd be happy with that!

Nod, you should be able to click on the thumbnail to launch a larger image?
 
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