Hello everyone, this is my first post, and hope someone can help. I just bought a 17-55 lens and I am a little confused about it. I know how to use the focal length zoom, but when adjusting the focal distance I dont see much of a difference from infinity to the closest setting. I have not shot with it yet, this is just my initial out of the box inspection. I will be using the lens on the M/A setting for the most part. I also read that if you are using auto focus that you should not manually focus the lens because you could ruin the mechanics of the lens... this is what is confusing me. Does that mean i should not be adjusting the distance on the lens? Can someone help me out? Thanks so much, I am in the learning stages of these better lenses. Appreciate your responses.