This is a must have accessory for semi-pro, professional photographers, enthusiasts, beginners and all levels of anyone creating imagery, be it with film or digitally.
It saves a lot of time in guessing what the true colour is from shoot to shoot.
Many a times, adjusting colour temperature is "guess-work" because there are so many variations of RGB.
The Colorchecker passport takes away the hard work, and creates a true starting point for post-processing or image adjustment.
For me, this is money well spent.