Autofocus not working for my Canon EOS Rebel T21 18-55mm Lens

[qualiareed]

Hello! I'm trying to troubleshoot what might be wrong with my camera lens. The autofocus keeps adjusting so that it's a little bit out of focus. It's still mechanically working just fine and the sensor on screen keeps finding a match (turns green), but adjusts so that it's a little out of focus every time. Is there any way to recablibrate the auto focus function? I have tried cleaning it both with the sensor cleaner and manually, but it hasn't changed it at all.

[Waddizzle]

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@qualiareed wrote:

Hello! I'm trying to troubleshoot what might be wrong with my camera lens. The autofocus keeps adjusting so that it's a little bit out of focus. It's still mechanically working just fine and the sensor on screen keeps finding a match (turns green), but adjusts so that it's a little out of focus every time. Is there any way to recablibrate the auto focus function? I have tried cleaning it both with the sensor cleaner and manually, but it hasn't changed it at all.

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Cleaning the image sensor is best left to the professionals.  The AF system uses a different sensor from the main image sensor, anyway.  

Does it look OOF through the viewfinder, or in Live View, or in the photos, or all of the above?  There is a diopter adjustment near the viewfinder, which can make the viewfinder images appear OOF, but the camera will still capture sharp images.

[qualiareed]

It's out of focus everywhere. I tried my other lens and it works fine, so it's definitely an issue with my lens.

[jrhoffman75]

You could send the lens to Canon for service, but if it's out of warranty it would most likely be less expensive to buy a refurb copy from the Canon eStore. 

[TCampbell]

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@jrhoffman75 wrote:

You could send the lens to Canon for service, but if it's out of warranty it would most likely be less expensive to buy a refurb copy from the Canon eStore. 

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That and... the 18-55mm lens has been revised.  The new version has better optics and a better (and quieter) focusing motor.  The old lens is likely not worth the cost to repair.  

The newer generation of the lens will have the suffix "STM" in the lens name (e.g. EF-S 18-55mm f/3.5-5.6 IS STM).  Avoid the non-STM versions (which are much older versions of the lens but you can still find some out there.)

[qualiareed]

Thanks for the advice! I'll go with a newer lens.