Michelle, Does it work sometimes or not al all? It is common if it fails sometimes but there is a problem if it will never focus. If you don't have enough contrast in your shot, even if it is properly lighted, it may not focus. There is no issue here as that is just the limit of the cameras abilit
This is why you can find a working zoom for a full-frame camera such as the EF 24-70mm and yet a working zoom for a crop-frame camera is typically 18-55mm (such as the EF-S 18-55mm f/3.5-5.6 IS STM). The EF-S lenses have the identical mounting coupling -- even the pin-outs for the lens control are identical. Canon EOS 350D Canon EOS Rebel T4i Canon EF-S 18-135mm F3.5-5.6 IS Canon EF 75-300mm f/4.0-5.6 III USM Canon EF-S 18-55mm f/3.5-5.6 II +1 more Reply Reply with quote Reply to thread ComplainI have the same problem, a Canon EFS 18-55 IS lens and the autofocus does not work correctly, but in my case only in one way. It retracts but does not extend. If I extend manually the lens, the autofocus retracts it till in focus, but if I retract it manually it does not extend till in focus, I can ear and feel something but no movementTake a look at Canon 18-55 autofocus (AF) repair , Canon 18-55 autofocus (AF) repair, Canon EF-S 18-55 IS disassembly and flex cable repair - Part 1. You can try opening the lenses and diagnose if this is the problem. I think you can find a replacement cable on eBay or import it directly from China (about US$12.00+shipping)