I have a sony dslr- a100 camera. I bought a 70-300 mm lens. the lens works well except that the gears for the auto focus have stipped.the lens still works but I have to manual focus it. I went and bought another lens of the same type. again the gears in it stripped and it needs to be manually focused. can anyone give me an idea of a lwhat lens to buy that would be about the same as what I have that would be more durable. the second lens I feel I really babied so the gears would not strip. but it didnt help. of course price is a factor but I am willing to buy better quailty. thanks Rick M Ransil