RF 24-105 f4-7.1 vs RF 24-70 f2.8 in daylight

[Michael Clark]

Are you sure about this ? It’s the first time I’ve heard it stated as a matter of fact.
I’ve only ever read rather woolly statements regarding how it must be to protect highlights, though when you think how much brighter the highlights can be over the rest of the image one third stop seems like naff all.
Have you a reliable source you can share regarding this ?

DxOMark ISO Sensitivities

DxOMark Derived Measured ISO