Mark
Ive been using the Nikon 200-500mm lens for the past two years and absolutely love it. It is extremely sharp. The image stabilization is nothing short of amazing. It is a big lens and has weight. I was looking for something smaller that still had good reach, something that would fit in my camera bag. After seeing rave reviews on the Tamron 100-400mm lens I finally decided to buy it. The color and contrast are good. The sharpness is very poor compared to the Nikon lens. Its like having a very inexpensive doubler on a good lens. The lens really seems to focus hunt as well. There were times where the images would seem acceptably sharp on some of the pictures I took but most often not. The Vibration Control is a joke. My Nikon lens quickly locks on focus and stays sharply in focus. It can be hand held at the slowest of shutter speeds. I was so disappointed in the Tamron lens that I returned it in exchange for another one. The second lens, the Vibration Control was marginally better but still not good. The second lens seemed to focus hunt slightly differently but with the same mediocre results. If I was just shooting pictures to only be used online, I would be ok with this lens. I often have very large Lightjet prints made from my images and the Tamron images just arent up to par. This was the first third party lens that Ive purchased and Ive learned my lesson.