The FoCal Calibration Check utility can assess the current state the phase-detect autofocus system of your camera/lens and determine if calibration is required.
This tool required NO user interaction, and can even run with (supported) cameras that do not have any focus adjustment capability.
You can open Calibration Check either from the Camera menu, or from the Calibration Check card on the Camera page.
In order to use Calibration Check, you need to ensure that the camera and target are set up correctly. Target Setup utility is an automated utility which will help you do this - all the information you need is here.
You can access Target Setup from the Target Setup button on the test footer bar, from Camera menu or from the Camera status page.
Once you have successfully confirmed you camera and target setup, you need to ensure that both Live View and non-Live View focus points are set to the centre point:
When the test starts, there is an information message that is shown to remind you to adjust the focus points for both modes to the centre, but FoCal will (currently) NOT verify this, so ensure you have correctly performed this step.
Once the setup steps above are complete, you are ready to run the Calibration Check.
You can start the test with the Start button in the Status tab, or with the Start button on the test footer bar.
The test requires no user interaction and takes a few minutes to run. The information obtained is updated as the test runs.
The Summary page shows the essential results for the Calibration Check:
The Calibration State card indicates the current status of the lens calibration.
The gauge runs from red on the left representing poor calibration, through to green on the right which represents good calibration (the marker is the black line – in the example above pushed to the far left as this lens is not well calibrated).
The Test Results Overview card shows a few essential test results. In this case, it shows that the lens is in need of calibration, and shows the number of measurements taken.
The Chart card shows the Quality Ratio chart, which shows how well the lens is performing.
The orange line shows the measurement results. If this line is mostly in the red area, the lens is poorly calibrated (as seen in the example above). If in the blue area it is acceptably calibrated, and in the green area it is performing well.
The Crops card shows the comparison between the best Live View (contrast detect) and best non-Live View (phase detect focus) images.
You can slide the bar in the crop images left/right to better review the comparison. You can also make the crop card large with the maximise button on the top of the card (this applies to any card which have this button).
Some measurement values are indicated below each side of the crops.
The Test Overview card gives basic information about the test – for example which camera and lens were used.
The example above shows a poorly performing lens which is in need of calibration. You can tell this from the Summary tab:
Contrast this with the following image of the lens after calibration
You can clearly see that:
See Settings - Calibration Check for further information.
See Details - Calibration Check for further information.
Calibration Check offers the following charts (click a link for detailed information):