I have gone through all the titles in this forum, but found nothing related to lens calibration. I have a focus problem, and have approached it according to several suggestions in this forum, such as cleaning the contacts, etc. I have found tips for calibrating lens for a number of cameras, but not for the D5100. I bought the camera new with two lenses: AF-S NIKKOR 18-55mm 1:3.5-5.6G and the other a 55-200mm. Both worked well for a time, but then I started getting blurred images. Since I am new at this, I am at a loss. Any advice, please?