I use this command (as Administrator):
exiftool -LensModel="Samyang 14mm F2.8 IF ED UMC AE Aspherical" -FocalLength="14.0 mm" -FNumber="14" -MaxFocalLength="14.0 mm" -MinFocalLength="14.0 mm" -TargetAperture="2.8" -m -overwrite_original_in_place IMG_xxx.CR2
After executing the command, PhotoLab recognizes the lens and uses the correction automatically.