It is, but it telescopes rather dramatically in use. Not necessarily a bad thing, I suppose, but I prefer a lens that stays the same size as it zooms or focusses.
Same here, the focus for a 70-200 f2.8 should be image quality, speed, robustness. A design that collapses is always a compromise and such a critical lens should IMHO not be compromised for serious usage.
Nikon and Canon were both right to make their mirrorless 24-70mm f2.8 non collapsable, while the Nikon 24-70mm f4 had to be collapsable. One line devoted to uncompromised quality/speed/robusness, the other line focused on compactness.
If I want compact I am willing to sacrifice on the aperture.
Besides, I see a clear lack of coherence in the design philosophy of R glass... the 24-70mm f2.8 is larger and heavier than it's DSLR counterpart, which I find crazy.
Cheers,
Bernard