I bought a Canon EF 28-105mm f/3.5-4.5 II USM lens for my Canon 350D. It works mostly fine, except after switching from AF to MF, I can't return to AF mode.
After I switch MF->AF, the lens doesn't activate the motor. Half-pressing the shutter will not result in focusing, the focus LED will be lit only if I point the camera at something at a distance it was manually focused for. Interestingly, the aperture works okay, I can see it opening and closing in Av mode as I rotate the turnwheel and hold the aperture preview button.
The way to restore the autofocus operation is either to remove the battery (normal on/off switch won't suffice), or to press the lens release button, rotate the lens a little, then snap it back to normal position - normal autofocus activity resumes.
Did anyone encounter such a behavior? Any solutions or suggestions?
(The lens was bought second-hand, and for a very bargain price, so I don't consider the fault a showstopper or a cause to return it to the seller, but I'd still prefer to have the AF/MF switch to work as intended.)