Tamron 17-50 worse then Nikkor 18-55 Kitlens?

[Uberhood]

Hello dear readers,

Recently I bought a second hand Tamron 17-50mm F2.8 lens (version with built in motor) to replace my current Nikon 18-55 non VR kitlens. At first I did not see much of an improvement, that was until I manually tested these 2 lenses against each other.
To my amazement the kitlens was better then the Tamron , which was truly shocking to me.

Firstly, the autofocus is more then twice as slow as the AFS Nikkor lens. If that wasn't enough, the accuracy of the Tamron is poor, especially in poor lighting conditions.

The real problem is the image quality. I made some test shots and the Nikkor lens clearly beat the Tamron in all of them. I tested all settings fully manually and used a tripod with self timer at 2 seconds to prevent shaking.

Here are a few test shots side by seed for easy comparison:

Center (1):
http://www.imageupload.org/?d=6522190F1
Notice the middle flower pot with leaves, the photo with the Nikon kitlens is way more detailed.

Center (2):
http://www.imageupload.org/?d=1F81D86E1
Notice the middle bush and left plant are way more detailed on the Nikon lens shot, especially at F3.5 aperture.

Corner:
http://www.imageupload.org/?d=B18C53661
Notice the white logo on the seat, the frame, and the red back light are also more detailed in the Nikon lens shot.

I'm out of ideas and thinking about selling the Tammy again. I've read about people complaining a lot about bad copy's, mostly with front focussing. I don't think front/rear focussing is the problem in my case, as this picture at F2.8 demonstrates:
http://www.imageupload.org/?d=6A4A1A511
Does anybody have any suggestions, am I doing something wrong, am I forgetting something, is it just the lens, is it the camera itself? How can I maybe fix my problem. Or should I just sell the "bad luck" I've bought. It failed to replace my kitlens for now.

Extra information if needed:
-Camera model used: Nikon D40
-Nikon lens: Nikkor 18-55mm F3.5-F5.6 non VR
-Tamron lens: Tamron SP AF17-50mm F/2.8 XR LD Aspherical (IF)
(NEW build in focusmotor)
-No filters attached during tests
-As said all settings manual

[TCav]

I think you got a dud. All independant test results indicate that even the stabilized Tamron 17-50/2.8 is superior to the Nikon kit lens.

See if the retailer will exchange it for another. If not, complain to Tamron.

[rlddg]

From what I understand, the Tamron lens has a six year warranty.

[DigMe]

The key words there are "second hand." I'm a believer in buying used but this kind of risk does exist.

brad

[tizeye]

Originally Posted by rlddg

From what I understand, the Tamron lens has a six year warranty.

To the original owner. Buying used = no warranty.

[Uberhood]

Originally Posted by tizeye

To the original owner. Buying used = no warranty.

I still have the recite, so theoretically I should be able to return it within 6 years, the only problem for returning is that the shop were it was bought is too far away.

[TCav]

Tamron's six year warranty is transferable. (tizeye, please take note.) Since you bought used, the original retailer isn't going to talk to you, but Tamron will. For warranty service, however, they may ask for the original sales receipt.

Talk to them. The worst thing that can happen is that they say no, but they might say yes.

[Uberhood]

An update for now!
I think I've found something new about my Tamron lens. It actually does have backfocus.
I did the 50mm test shots, again the Tammy lost. But then I noticed the background was sharper on the Tammy. So after the Tamron autofocussed I switched to manual and adjusted the focus ring in tiny steps. Decreasing the focussing distance after autofocus made some of the Tamron pictures beat the Nikon kitlens. I did more tests on that, also at 18mm, same results: adjusting the focus ring made the picture quality a lot better.
Will do some more testing outside during daylight tomorrow.

If I want Tamron to fix my back focussing problem, do I just contact with Tamron EU? I do have a copy of the recite so it shouldn't be a problem

[TCav]

Ok, that six year warranty is from Tamron USA. I don't know what warranty you might get, but, yes, just contact them directly.

[tizeye]

Originally Posted by TCav

Tamron's six year warranty is transferable. (tizeye, please take note.) Since you bought used, the original retailer isn't going to talk to you, but Tamron will. For warranty service, however, they may ask for the original sales receipt.

Talk to them. The worst thing that can happen is that they say no, but they might say yes.

Tamron-usa Warranty... source reference (and 800 number) http://www.tamron-usa.com/lenses/warranty.asp

The limited warranty set forth below is provided by Tamron USA, Inc. and is applicable to new Tamron Photographic Lenses purchased in the USA through an authorized dealer. Open box sales or used equipment do not apply. The Warranty shall not extend to anyone other than the original purchaser of the lens or the person for whom the lens was purchased as a gift. This Warranty is valid only in the Continental United States, Alaska, and Hawaii, and is valid only upon presentation of a valid proof of purchase from an authorized Tamron dealer (valid proof of purchase must be a dated bill of sale that includes price, model and serial number of lens and/or when fully completing Tamron’s Online Warranty Registration at www.tamron-usa.com).

That language is fairly consistent industrywide as each distributor seeks to limit gray market sales that they didn't originally profit off of AND AT THE SAME TIME limit their longer term liability by removing resales of authorized products. That is why when considering the purchase of a used item there are 2 key questions to ask. 1) Is the price savings between new and used at least enough to cover one repair? and 2) Is a used price plus a 3rd party warranty contract of similar length still providing a savings over new?

Still wouldn't hurt to talk to them though with the phone number provided.