Mar 22, 2007, 18:19
For the curious, the world's largest telephoto lens ever produced for civilian photographic purposes, the Zeiss AP Sonnar T* 4/1700 - has a focal length of 1700mm, and provides 21x magnification. It looks more like a sub or a torpedo to me, than a photographic instrument. 

http://www.engadget.com/2006/09/13/carl-...hoto-lens/

Quote:Never before has the world of photography seen such a lens. The ZEISS Apo Sonnar T* 4/1700 was developed by Carl Zeiss for a customer with very high demands and a special interest in long distance wildlife photography. To achieve the highest possible image quality, the customer decided on the Hasselblad 203FE 6x6cm medium format camera and ZEISS lenses as the best combination for his special needs.This just amazing - I'm speculating that it must be vehicle mounted, since there's no possible way a human could carry it around. Plus, being fixed focal length, the user would need to move their position to adjust the framing...

Quote:The design of the ZEISS Apo Sonnar T* 4/1700 required new lens assembly techniques and quality assurance methods never before applied in photo lens production â even by Carl Zeiss' normally high standards. The finished lens weighs a staggering 256 kg (564 lbs.), placing unique demands on the focusing mechanisms. To address this issue, Carl Zeiss developed a totally new way of operating a telephoto lens, including servo controlled aiming and focusing systems like those used in large telescopes and similar instruments for astronomical scientists.http://www.dcviews.com/press/Zeiss-Sonnar-4-1700.htm
http://www.engadget.com/2006/09/13/carl-...hoto-lens/