When looking to get a used lens, I was told by a fellow (amateur) photographer to avoid buying lenses involved into video shooting. He didn't gave any explanation and left before I could ask him.
When this remark arose, we were talking about a used Canon 50mm f/1.2 L USM : the seller wrote that the lens was used for making short video clip in low-light condition on a DSLR. So the remark seemed to be targeted toward lenses "designed" for still photography (no mention of T-stop).
What could happened to a lens used for video versus one used exclusively for still photography?
I get that the lenses might get exposed to light for a long period, but it doesn't seem very different from my use on vacation, when my front caps can stay off for a while... It seems to me that the sensor will be damaged long before the lens.
Regarding autofocus system, shooting movies is often on manual focus, but the focus motor can indeed be continuously working for a few minutes repetitively.
Am I missing something or can I disregard his advice?