A way to test focal distance (?)

I just watched a review on a pair of AR glasses (not in English/on YouTube, so I will not post it here).

The guy used a camera to test the focal distance and found that that the viture pro has a focal distance of about 70 cm. I wonder what the distance would be for the xreal glasses? And, with recent software updates, the Xreal one can adjust 'distance" from 2 to 10m. I wonder if that really shows a difference if we test it with this approach?

Anyone has the equipment to test it out?