The pinterest account hosting that image did not identify the lens, sadly. I did a little googling but couldn't find an exact match. He/she did appear to be a Nikon fan. I found Nikon apparently made a set of two-piece super long telephotos (I saw one at 1200mm). There was a focus mechanism that was separate, and you attached this to one of the lenses (I think there were three of them). But there were other brands of really long lenses, too, so I cannot be sure it was Nikon.