Reversed Zoom Ring

Hello all

A friend of mine, who shoots Canon, complained about my 70-200mm VRII having a reversed zoom ring. Admittedly all my filming lenses are the opposite to the Nikon but I just took it with stride and ran with the reverse on my Nikon lenses.

I'm curious as to why some manufacturers have their zoom rings go one way or the other. Nikon and Panasonic/Olympus lenses are telephoto to wide (left to right) vs. Canon seems to be wide to telephoto.

Any reason one way or the other?

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-A