Competes with the Nikkors, but falls short in quality and performance.
I've tried at least 4 copies of this lens, 3 of the Nikkor 70-300mm VR, and 2 copies of the Nikkor 55-300mm. Consequently, I have some experience using and evaluating these lenses.
First,lets start with the positives. The Tarmon is a large lens that feels good to the touch. It looks good and the materials feel as if this is a well made lens. The size and weight does make it an excellent match for FX bodies. The VC, at first glance (more on this below) gives you a satisfying lock of the image that gives the impression that this stabilization system is far superior to others. The autofocus is fast and great for action shots.
Now, for the not so good...Unfortunately, quality control is all over the place with this lens. Out of the four copies tested,all had some image quality problems. Two had decentering issues and two where severly front focusing (+8 & +13 correction units). Mechanically, there were issues as well. All exhibited a somewhat curious change in the required friction to make it from one end of the zoom range to another. In the middle of the range, the lens requires greater force. It's not terrible, but this is something that neither Nikkor exhibited. The build quality was also all over the place depending on the copy. Last observation, this lens is much bigger than the Nikkor 70-300mm VR.
The VC also has major issues. I can confirm Ken Rockwell's findings on the VC. At first, it is amazing to observe how solidly the image appears to stabilize. You see no floating at all, It's rather impressive. However, in real use, this stabilization system is subpar. Like other systems, the image takes a moment to stabilize. However, unlike Nikon's system, which partially stabilizes the image while autofocusing and then fully locks the stabilization upon shutter release, Tamron appears to do this at the last moment upon shutter release and requires further time even after focus locks to stabilize the actual image. Unfortunately, the solid stabilized image in your view finder gives no clue as to this odd behavior. So why does that matter? If unaware of this behavior, you will take many shots that look stabilized in your view finder, only to find out later that your images are blurred. What is required is that you take a pause after focus prior to shutter release. In fairness, most stabilization systems require this. However, Nikon guides you in the view finder by suddenly giving you a more stabilized image. With the Nikon VR, you can even enjoy the benefit of partial stabilization even if you take the shot without waiting for the VR to fully set in. NOT SO with the Tamron; it's all or nothing. Consequently, you are left guessing as to when the VC is fully engaged as the viewfinder image remains constant throughout. Now, you can do away with this problem by just turning off the VC and using a tripod or just focus, lock, pause for a while, and then release the shutter.
Now for the autofocus...All copies had fast autofocus. As fast if not faster than the Nikkor 70-300mm VR. However, its accuracy fell short of the other two Nikkors. My keeper rate was 6 out of 10 for most situations, while the two Nikkors had hit rates of 8-9 out of 10. Tamron neeeds to work on the autofocus algorithms.
Lastly...sharpness. Get a good copy of any of these lenses and it will be sharp. Unfortunately, all copies of the Tamron had issues which made their image quality very disappointing. Where is the QC Tamron?Read full review