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I hope this is posted in the correct Forum. That was my intent.
I have tried to find this information using search but could not find it. If it is there, please accept my apology and tell me where to find it.
Through an incredible act of clumsiness, I have had to replace my D80 and older 18-200 lens. (Yeah, major embarrassment)
I am replacing the D80 with a D90. My quandary is on lens choice.
I will either use the new Nikon 18-200 as in the subject line, or go with the Tamron 18-270 3.5-6.3 Di II PZD.
I cannot find any reviews or commentary on the Tamron and would like to know what to expect regarding differences in Image Quality and Build Quality, and make a comparison of the two.
The price difference is only $100, so the deciding factor will be performance.
I was reasonably happy with my older Nikon lens and the IQ was very acceptable, but the additional versatility of the longer zoom intrigues me.
I would expect the Nikon lens to be better, but just how much and would it be a noticeable difference? The 18-200 was versatile, but I don't want to trade off noticeable performance. The key word here is "noticeable".
I do crop, usually a little, sometimes a lot, and view on a large screen Mac. The largest prints I make are 8x10, but I could occasionally go larger.
Any help in making a determination on the lens or where to find information is appreciated.
Thanks,

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David

You can easily judge the character of a man by how he treats those who can do nothing for him.

I had the very good fortune of being able to do my own lens testing, admittedly not professional, but it is all I could do. But since this is how I generally view my photos, it was practical.
I found a camera shop that had both lenses in stock and I took some side by side pictures with my own camera, set on program, then took my camera home and downloaded the photos to my computer.
I took pictures of displays on a wall inside the store, flowers outside the store, and pictures of my wife both inside and outside. I used inside/outside as I thought the lighting might make a difference. It did. I took the same pictures at focal lengths of 18, 50, 100, 150, 200, and just for curiosity, 270.
When I viewed full size on my screen, I could discern no real or noticeable differences except the colors in one or two shots were slightly brighter with the Nikon. The different focal lengths did not seem to make a difference. I did see differences when when I enlarged and cropped. I did not expect what I got.
Here is where I show my lack of technical knowledge. In order to keep things as consistent as possible, I enlarged by hitting the button on my computer 4 times. I have no idea how much this actually is, but my goal was to go big and stay consistent. Hitting the button and using this setting was about the most I ever do, so I thought that it was valid.
For the flower pictures, detail and color was extremely sharp with excellent contrast and they were comparable to each other at all ranges except 150 and 200. Surprisingly, the Tamron was actually slightly sharper than the Nikon, but only very slightly.
For the outdoor pictures of my wife, I enlarged tot he point where all I could get was her eyes, eyebrows, and hair. Again, both lenses were comparable up to 150 & 200. In this case, the Nikon had slightly sharper images, being able to see better highlights on the hair and individual hairs were more discernible.
I saw greater differences in the indoor photos. I used only the indoor store lights as I didn't want to introduce another variable of the strobe.
I was at a distance of approximately 70-80 feet from the wall. At normal viewing, the photos were the same but again, the Nikon color and contrast were just slightly better, and you had to really scrutinize to see any difference. My wife called it nit-picking and she didn't see any difference. Maybe, because I am admittedly a Nikon fan, I wanted to see more difference than there was. In reality, it was a subjective call and I admit to being partial.
I enlarged the photos to the point where I could read individual letters on the tags on the merchandise, and this was a considerable amount. More than I ever would normally do, but I was enjoying the testing.
Once at the extreme enlarging, the Nikon really showed better clarity and less fuzziness on the individual letters on the tags, but again, while noticeable, the differences weren't huge, but they were there. Neither was incredibly sharp, but I think the Nikon took the lead here.
At the end, what surprised me most was that there wasn't more of a difference in the two lenses and that in a couple of instances, the Tamron appeared to perform better.
The Nikon did focus faster in most cases, but the Tamron could never have been called slow. It was more like one was really fast and the other was incredibly fast.
The Tamron was definitely lighter and that could make a difference if you're going to have it hanging off your neck for very long periods of time.
I never had any problem with either lens as far as creep or any mechanical problems.
Something I did not understand is that I saw veery little difference in image coverage between 200 & 270. Yes, the 270 did bring you in closer, but it was only slightly. I expected a more noticeable difference.
The price of the Tamron was slightly lower than the Nikon and the overall performance was really quite similar, but slightly better with the Nikon.
If I hadn't been such a stickler and gone to enlarging more than I would in reality, I probably would have been happy with either lens.

_________________
David

You can easily judge the character of a man by how he treats those who can do nothing for him.

Interesting report David. Did you already decide which one to get?
There is a professional test of the Tamron here, albeiot on a Canon 50D. The lens got 2 stars (out of 5) and had some pretty nasty lateral CAs. The Nikon scored 2.5 stars, so your impressions should be quite right: not much of a difference to be seen there.
I know from personal experience that the Nikon has a weak spot around 100-150mm but at the other focal lengths is quite amazing for such an extreme zoom. Personally I'd get the Nikon again.

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Hi, Thomas.
I did decide on the Nikon. Partly because it is what I am used to.
Nikon has a discount on the lens when you buy a new camera but there is also a rebate on the Tamron, making the actual difference in price only $125.
I could have been very happy with the Tamron, but I could afford the Nikon so I went with it.
I spent the day at the zoo the other day and kept thinking how much easier it would be to carry the camera all day with the lighter lens.
All in all, it's a trade off. Both offer excellent value. You just have to pick and choose.
Thanks for asking.

_________________
David

You can easily judge the character of a man by how he treats those who can do nothing for him.