Here are macro photos taken with my Tamron 100-300mm lens on my Pentax ist DL2. Most of the time, the photos come out sharp and clear.
Just got an older model Tamron lens from a camera shop today and immediately put it to use around the sanjo area of Kyoto. It focuses quickly on targets and the photos come out very nice. In order to focus on a subject, the main object has to be about a meter or more away. (I haven’t measured the distance yet, so this is just a guess from when I tried focusing on some things today!)
Here are photos from this lens: