The iPhone 5 on display after its introduction during Apple Inc.'s iPhone media event in San Francisco, California. Credit: Reuters/Beck Diefenbach
According to the Daily Mail, some users hope this is a software bug that can be fixed with an update.
But some blame the sapphire crystal lens, in which case a fix would be unlikely without a product recall.
According to the report, some users have taken images of the same location with the iPhone 5, iPhone 4S and iPhone 4 to highlight the drop in image quality.
Apple has not yet officially given a comment, although the firm's tech support teams have allegedly told users the problem is 'widespread'.