Canon 50mm f/1.2 vs 50mm 1.4 - How Much extra Light?

An updated video of my last..

This one actually shows right at the end the extra light you get from the 50mm 1.2

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1 X Canon 50mm f1.2 L Series Lens

1 X Canon 50mm f1.4 Standard Lens

1 X YONGNUO YN-160 LED Video Light SLR Camera DV Camcorder

1 X Canon 5D Mark II

1 X patient wife

Trying to justify the $1000 extra price tag for the 1.2 Version....