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.
I'm unfamiliar with the exact equipment, but if this is like the 18-55mm kit lens on Nikons, it's not terribly robust even though it's optically good.
Just to be sure, I'd switch to Live View (or whatever Canon calls using the LCD instead of the viewfinder). See if it behaves the same then. If you can zoom in the view, you should be able to manually focus very precisely, and any inability to get good sharp images is pretty sure to be the lens. It also uses a different Auto focus system, so if AF still does not work properly, it points to the lens as well.
Is it out of focus at all distances, or simply unable to reach some specific distance? I'm just wondering if there's something like dirt or a foreign object preventing it from going all the way in one direction. Most zoom lenses these days are not parfocal, which means that when they zoom they also need to be refocused. If there's a glitch in the focus, you might lose the longest or shortest distances at 55mm. On the other hand, if at 55mm nothing is in focus, then it's not that.
It would be a great help if you could find another lens to try out, too. Any friends, acquaintances or dealers around who might have a lens to try?
Yes, the lens is truly the weak link in this system, being made in large part of plastic, and just feeling pretty destructible in general. I'm guessing it's a failure in the sensor. And, being able to use 18-52mm successfully is not terrible. I can live with that.
Truth is, I was a Nikon user for many years, owning a D50 until it began having shutter issues, and became unreliable. I pushed a lot of images through that camera. It took me awhile to like the Canon images after using Nikon for so many years. There was definitely a difference.
I'm not sure about the Canon lens, but the Nikon 18-55mm kit lens in its various forms can be found quite cheaply used, at places like KEH.Com, or B&H, and probably on Amazon and so forth. If the lens satisfies in other respects, the best solution might just be to get another one used. As an alternative, I expect there are some better quality lenses in a similar focal length range, either by Canon or by third parties such as Sigma.
Of course if you're on the move, you might have some difficulty doing it by mail order, but if you stay still for a week or two, a place like KEH is a good possibility. They ship pretty fast. B&H is also quite fast.