If you’ve ever noticed your camera is no longer focusing properly, you may be in need of an autofocusing tune-up. Thankfully, this is usually a job you can perform yourself using a few simple tools: a measuring device—like the Spyder Lenscal—and a tripod.

In the video below (produced for our sister pub PDN in collaboration with photographer David Patiño), we show you how it’s done.

The exact procedure is called slightly different names depending on your camera brand. Sony and Canon call it AF Micro Adjustment. Nikon simply calls it AF Fine Tuning. Either way, it’s typically an option that’s only available on higher-end camera models.

Performing an AF Micro Adjustment/Fine Tuning is essentially a way to tell your camera body how to focus when a given lens is attached. You’re not actually changing anything in the lens itself, simply how the camera’s focusing system reacts when a given lens is attached.

Some tips to keep in mind when performing an AF fine tuning:

• Shoot at the lowest native ISO setting of you camera
• Shoot in mirror lock-up mode
• Shoot on a tripod
• Shoot tethered
• Position your measurement tool 25-50 times the focal length of the lens you’re testing
• AF fine tuning is a trial-and-error process so be prepared to invest some time to get it right