I have an SL1, with the EFS 18-55mm lens on it. I have owned the camera and lens as a package for about two years. Up until now I've had no issues. Yesterday while taking some photos at a nearby archaeological site, I noticed the lens having an issue focusing when fully racked to 55mm. No matter what mode, AF or MF, it would not focus. I'd go slightly wider, and it worked as usual.
When I got home, I cleared all the settings to factory default, removed the battery for several minutes, and replaced the card. Same issue.
I then took some test photos, trying to determine where it was loosing focus. I checked the details section after I loaded the photos on to my laptop, and discovered that while the focus would be off at 55mm, at 52mm it worked just fine, as before.
I'm guessing it's a lens issue, but would appreciate any offers of valid information.