The company's website says the issue applies mostly to phones sold between September 2014, when they were released for sale, and January 2015. Apple (AAPL, Tech30) said these phones may have a defective component in the camera and will take fuzzy pictures.
The issue is with the iSight camera on the back of the iPhone 6 Plus -- and not the "selfie" camera -- according to the company.
Apple said it will replace the cameras for free. Affected customers can go to an authorized service provider, any Apple store, or contact technical support to set up a swap. The company noted wireless carriers are not able to fix the issue.
Owners can check if their phone is included in the recall by entering a serial number on this website. Serial numbers can be found under "Settings > General > About" on an iPhone. It's also on the device's original box and can be looked up on iTunes.
Issues have been reported with the phones since last fall. One thread about the problem on Apple's support site has more than 100 replies reporting issues with focusing the iPhone 6 Plus camera.