I just received a new Tamron 18-250 in Sony mount, and manual focus if stiff and noisy on the a350, 5D and 7D bodies, while auto focus is normal and accurate. The focus ring turns freely when the lens is off camera. Other lenses focus manually smoothly and silently or nearly so on these bodies. I have the same lens in Pentax mount and manual focus there is as expected - turning freely and almosdt noiselessly on Pentax bodies, so this new lens doesn't seem to be operating normally. I know other Sony owners have this lens - what is manual focus like on your cameras?
**** Never mind - I sent it back for an exchange. ****