Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Sticky and Soft

Bought this for my son as a backup to his Sony 75-300 that has become difficult to zoom because of a dirty environment. He uses it for rodeo photography with his old Alpha 100. Has been a good business for 5 years but dirt is a problem and most shops don't want to clean a Sony lens. The Sony is still working fine but is harder to zoom because of built up dust.Thought we would take a chance on this lens and just replace it every couple of years because of the dust. Reviews looked OK but the Tamron lens doesn't work for us.Compared even to the (used gummy) Sony lens it was sticky and especially hard to zoom near the 300mm range. This may be OK for still nature shots but it kills fast moving sports action shots when you have to make the camera twitch to zoom in. Also compared to the modest Sony 70-300 the Tamron 70-300 was noticeably softer in the same shooting conditions. I would gauge it at about 30% softer.We returned it. Wish it would have been more serviceable.