I just got a new Tamron 28-75 f2.8.
First impressions are that the image quality at 75mm f2.8 at infinity or distances larger than 15ft. is bad. Stepped down to f4.0 there is great improvement, although infinity doesn't improve till f8.
At close distances, the IQ is very good, even wide open - no complaints.
Is it reasonable to expect such bad IQ for a lens in the $350 price range at its longest and wide open? I've heard zoom lenses are especially bad at infinity range, but cannot find any article on the web to confirm that.
Here are pictures (100% central crop) of a parrot at f2.8 and f4, and an elephant at f2.8 and f4. The parrot was about 15ft away and the elephant was at infinity.
Is this normal lens softness or a lens defect?