If the new ET-83G (or was it H) hood is for this one, then it's probably 77mm. Historically all the E*-83* hoods were for lenses with 77mm filter thread, and hilariously enough, they're all cross-compatible so ever since losing the hood for my 100-400 I'm using the one from 24/1.4 II on it, and it fits...
But 77mm filter thread for a 70-200/4 lens is a bit on the large side whereas all the other lenses had 67mm filter threads until the previous Canon and then the Panasonic...
But 77mm filter thread for a 70-200/4 lens is a bit on the large side whereas all the other lenses had 67mm filter threads until the previous Canon and then the Panasonic...