I'm in currently in Las Vegas and I am having massive problems with my 28-105mm f/4-5.6. The first thing I noticed it doing was when ever I put it onto my camera and turned the dial to any of the modes, it would pause for about 10 seconds before showing anything. Second I noticed that on my LCD screen it keeps saying Manual Focus is switched on while the lens will be switched to auto focus. Third it keeps trying to tell me that the battery is dead and switching off (I tried 2 different battery sets one being brand new). I don't have any digital cameras with me but here is what I have examined from the outside of the lens... The lens is loose (Part that actually zooms in and out, not base attached to camera) and will easily move back and forth with the touch of a finger. There seems to me more silver present between lens and the camera, thought I might just have not noticed it before. The sensors or whatever you call them on the lens seem fine, though there does seem to be a smudge on the bottom of the lens. I know it is not my camera because after the 28-105mm started acting up I put on my 17-40mm and had no problems at all. The so-called "dead" batteries from before now worked. The camera knew when I had AF and MF selected, and when I first turned it on the LCD screen quickly gave me all my information. **Now after the lens has been attached for about 15 minutes it seems to be working fine? I have no idea what the lens is doing. Though I knew I could expect it to go bad on me somewhere down the line, it is the kit lens and made out of almost plastic material. I looked in the phonebook and found that there are some Canon authorized places around here so I'm going to try and go there tomorrow. But if it keeps going good and bad on me, I'll get to experiment some new things with my 17-40mm. If you have any ideas as to why it is doing this please help. Thanks.