Getting the target in the right place and set up appropriately is important. To save any concern over whether your test results are valid, FoCal has a Target Setup Utility which shows you a Live View display of where your camera is aimed.
Guides on screen shows you if any adjustment is needed – from the size of the target image, distance from the camera, any rotation of the target, or even whether the camera and target are parallel! When everything is set up right, a big green tick shows you that you can continue with any tests:
FoCal offers lots of ways that you can test and check your camera, and most of these require the use of a calibration target. For the test to give the best results under the widest conditions, the target should be set up in a fairly specific way, and the Target Setup Utility is designed to make this both as easy as possible and to give you confidence that everything is correct and ready for testing.
A word about FoCal Targets
FoCal is supplied with a set of image files which can be printed on a standard printer – you can find these in the Target Images directory of the Zip files (Windows) or Disk Image (Mac), or you can download them from the Document Downloads page. The following files are available:
- FoCal_Target_xxx.pdf – this is the standard target for all tests except the MultiPoint Focus Test, and is a vector graphics file so can be printed at any size while still retaining the best possible quality. However, some printing companies cannot print with PDF files.
- FoCal_Target_xxx-600dpi.png – this is a copy of the target above but exported at 600 dots-per-inch in PNG format which can be printed by all printers. If this image is made too large then it will start to become blocky.
- FoCal_MultiFocus_Target_xxx.pdf – this is the target for the MultiPoint Focus Test. Again, this file can be printed at any size but may not be handled by all printing companies.
- FoCal_MultiFocus_Target_xxx-600dpi.png – this is the MultiPoint Focus Test target exported in a format which can be printed by all printing companies.
Note that the xxx in the filename above represents a version number and may be updated from time to time.
The target should typically printed at A4 or US Letter size, using fine quality paper and ideally an inkjet printer. If you use a laser printer, you need to be aware that the toner can be a bit shiny so you have to be careful about how the target is lit – it’s important that no reflections are aimed back at the camera as this can affect the analysis quality. If you use an inkjet printer – especially with matte paper – you will achieve a fantastic contrast between the black and white areas.
What does the Target Setup Utility actually do?
The Target Setup utility is intended to make it quick and easy to both set up the target and to have confidence that you’ll get the best results from any tests you then run. It does this by capturing Live View images from the camera and analysing them to determine the position of the target.
In use, you simply have to start the utility, then move the camera and follow the on-screen icons to get everything set up right.
Starting the Target Setup Utility?
How you start the Target Setup utility depends on whether you’re using FoCal on Windows or Mac:
On Windows, click the Show Tools button to show the tool panel, then click Target Setup to bring up the utility:
Alternatively, you can press the T key to bring up the utility.
On the Mac, you can bring up the Target Setup Utility with the CMD and T keys, or by choosing Target Setup from the Tools menu.
Positioning the Target
The printed target should be as flat as possible against a solid surface so there’s no light shining through the target (this will seriously affect the analysis results, so don’t attach the target to a window etc). It should also be mounted approximately parallel to the image sensor, so if you took a picture of the target it would be straight on to the camera. The target should also be straight up (so the writing on the target sheet is the right way up).
With the camera aimed at the target, you can click Start on the Target Setup Utility – it will focus on the target and then start Live View and give a real-time image of the view from the camera. The target search algorithm is quite intensive so it’s disabled by default in order to give a smoother video image, but if you click the Target Search button you’ll get information about how well the target is positioned.
If the target is set up perfectly, you’ll see a green tick in the middle of the image:
Let’s take a look at what would happen if the target isn’t quite right, for example:
The red arrow is telling you that the target is too far to the left, so you should move the camera on the tripod a little to the right:
Now the target is not straight up (indicated by the red circular arrow), so you’ll rotate the camera or target around to make the target upright:
Now the target is a little too low, so raise the camera to get to the perfect position.
The target doesn’t have to be absolutely lined up with the circles in the centre, but if you click the Zoom button you’ll see the image zoomed to maximum and you can quickly align the crosshairs (visible when Target Search is disabled).
Using the Focus Tools (FoCal Pro)
The Target Setup Utility also offers the ability to focus the camera, which is required before running certain tests e.g. TurboCal and the Aperture Sharpness Test.
By clicking the Show Focus Controls tick-box, the extra panel on the right of the window appears. This allows you to do the following:
- Phase Detect Autofocus – using the normal camera AF system to focus on the target
- Contrast Detect Autofocus – using the camera’s Live View AF system (if available)
- FoCal Autofocus – an optimised focusing routine which is designed to get better results than the in-camera autofocus
You can also manually adjust the lens focus point by small amounts in towards the camera (Near) or away from the camera (Far) as well as clicking “Update” to take a new reading. The combination of these controls allows you to finely control the quality of the focus on the target as well as adjusting focus on manual focus lenses before running tests where perfect focus is critical.
The chart and buttons are colour coded as follows:
- green is Phase Detect autofocus
- blue is Contrast Detect autofocus
- purple is FoCal autofocus
- orange shows the effect of a focus step towards the camera (Near)
- red shows the effect of a focus step away from the camera (Far)
- yellow takes another sample and adds to the chart
For further information about this and other tests, the latest FoCal Manuals are available from the Document Downloads page.