How do I print the FoCal Target?
The FoCal Target is an important part of how FoCal works, information for self-printing the target can be found below.
We've tried a lot of different printing techniques and found for best results a standard inkjet printer set for high quality printing on matte heavyweight A4 or US letter sized paper works very well. Once printed we suggest to mount the print on something stiff that won't warp or deform over time (foam core or similar is good).
Usually we suggest to avoid using glossy or semi-gloss paper, it can work ok but glossy paper can end up with reflections from the lighting rather than showing the actual high contrast black and white design. Key thing is that the target design has good contrast when viewed from the camera position. If using a reflective print make sure the lighting is not reflected instead of the target design, stick to a matt paper is usually a safer option if not sure.
Download the target image file by clicking FoCal Target – 600dpi PNG which ideal for most users. There's a vector version that can be scaled without loss of quality but it is not generally needed Vector Target.
A target printed to A4 or US letter size works well for most situations, if you're calibrating wide angle lenses at far distances you can print the target a little larger (or scale the image so the target design fills to the edge of the paper). In those cases the estimate of target distance might be incorrect. It's possible to enter the target width within FoCal under Help > Settings > General Test Settings > Target Width.
In order to determine the Target Width users will need to measure the printed target (amount should be measured in "mm") along the line as shown on the printed target.
Note, user entered target width information is only to estimate the target distance for presentation, it makes no difference to the calibration itself (i.e. despite the user interface reflecting an incorrect estimate for target distance the calibration results are unchanged).
The target image files are also included within the FoCal software download. Self-printed targets are the most popular option, if you prefer you can purchase a pre-printed FoCal Target instead. Pre-printed or Hard Targets are available direct from Reikan in the online store as well as via our Reikan US distributor. Pre-printed targets do not need to be measured as FoCal will recognise the design and apply the correct dimension automatically.