Summary: Went to Veterans Day Parade to use lens for the first time. This is my first really good lens. It is heaver than I thought it was going to be, but not too heavy to walk around with, and hand hold. For me the quality of the pictures were just excellent. The focus was very fast, and accurate. I was shooting people who were walking and marching around. I also used the manual focus which was very smooth. For me it is an excellent price for the quality.
Summary: So it took a little deliberation when rating this lens and deciding between 4 stars or 5 stars but after some thought I came to the best conclusion i could. Now at this point obviously i settled on 5 stars and while this lens is by no means flawless it is still perfect. Lets go ahead and start with the Pros.
Excerpt: First I'll address the issue that everyone is talking about: the slow autofocus. It really isn't that big of an issue unless a subject is coming directly towards you. If you are upgrading from the Nikon 55-200 or even 70-300, the autofocus on this lens will be faster than those. I've used this lens for sports (football at night, basketball) without a problem. When you compare it to the Nikon and Canon versions, the autofocus is a little slow but it's not a big deal.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Nice Bokeh
The best fast telephoto zoom lens for the Pentax mount.
Jerry Jackson Jr., Amazon
6 September 2014
Summary: The Tamron 70-200mm f/2.8 is a no-brainer for the Pentax mount. The closest lens that Pentax has to this in the current line is the 50-135mm f/2.8, but that lens is known to have problems with its in-lens SDM autofocus motor (many of those lenses end up failing and have to be converted over to the camera body's "screw drive" AF). The Tamron 70-200mm uses the screw drive in the camera body for AF so there is no reason to worry about AF failure in the lens.
Summary: Being relatively new to more serious photography, I'm trying to avoid the temptation of getting every gadget and lens and add-on I can before I actually find a real need for it. That being said, after many reviews, reading (Stunning Digital Photography and the associated buying guide are great books for this), I decided I wanted a 70-200mm f2.8 lens for my Sony Alpha A57.