Carl Zeiss and other Sony zooms. Built-in zoom lock?

[plevyadophy]

I was recently fiddling with my old (and much loved) Sony R1 and it's beautiful Carl Zeiss lens.

I then noticed something I had pretty much taken for granted. Namely, ZERO zoom creep from the lens (even if held facing downwards and shaken).

Being the nerd I am, I decided to investigate how this was possible. I noticed that if I gripped the lens by the front/lens hood and pulled, the lens refused to to extend to zoom position. The ONLY way to extend the lens is to turn the zoom ring.

WOW! What a clever design. It's just so neat. It's just there ready and waiting, constantly active, no messing with zoom-lock buttons. And the strange thing is, Sony never boasted about the feature in any of their literature (a bit like how Nikon were making noises about the new thermal protection feature in their SB-900 flashgun and getting plaudits from reviewers because of it, whilst Sony had the same feature in their new HVL-58 flashgun but made no mention of it unless you happen to read the manual).

So I am wondering, how many Sony/Carl Zeiss lenses have this feature?

Thanks in advance.

Regards,