The 1600mm f/5.6 Leica is certainly the most expensive lens that we know of officially, but there are some other contenders for the crown. Chief among them is the Zeiss Apo Sonnar T* 1700mm, f/4 — it had a wider max aperture, longer focal length, weighs 564 pounds (256kg), and connects to a Hasselblad 203FE 6x6cm medium format camera. Unfortunately, we have no idea what that Ziess lens went for, or even who commissioned it — just that it was emblazoned with the state logo of Qatar. Who knows, Sheikh Al-Thani may have that one, too.