When you half-press the shutter button on your DSLR and you get that little focus beep, things might not be quite as perfect as you think.
Did you know you can adjust the autofocus on your DSLR?
A lot of mid- and high-end DSLRs have a setting called AF Microadjustment or AF Fine Tune which allows you to slightly adjust the focus position that the camera determines. The camera manufacturers give you this setting in an admission that production tolerances and day-to-day usage of a camera can affect the performance of the autofocus.
Canon AF Microadjustment
Nikon AF Fine Tune
The setting is just a number… but how do you pick it? There are many different interacting components of the AF system, and you can’t reliably pick the correct value without checking and rechecking your settings.
And here’s where FoCal comes into the picture – it takes all the guesswork out of the calibration. It shoots, validates, analyses, checks, adjusts… all this complexity is hidden away (unless you choose to see it), so it’s just a simple operation to get the best from your camera and lenses.
If you want to dig a little deeper, check out this simple description of how DSLR autofocus systems work and why they need adjusting.
FoCal is computer software you install on a PC or Mac, and a special target you attach to a wall. You connect your camera to the PC with the standard USB cable and start the software.
FoCal guides you through the correct positioning of the camera and target, then you can run any of the tools at the touch of a button.
FoCal works with Canon and Nikon DSLR cameras that support AF Microadjustment/Fine Tune – see the Supported Cameras page for more details.